Merge pull request #40148 from RevoluPowered/unit-test-revamp

Added doctest unit test framework

8 files changed, 1136 insertions, 1397 deletions

diff --git a/main/SCsub b/main/SCsub
index 7a301b82bc..bf188d7328 100644
--- a/main/SCsub
+++ b/main/SCsub
@@ -9,7 +9,6 @@ env.main_sources = []
 
 env.add_source_files(env.main_sources, "*.cpp")
 
-
 env.Depends("#main/splash.gen.h", "#main/splash.png")
 env.CommandNoCache("#main/splash.gen.h", "#main/splash.png", run_in_subprocess(main_builders.make_splash))
 
diff --git a/main/main.cpp b/main/main.cpp
index a500e173a2..e60bdda18d 100644
--- a/main/main.cpp
+++ b/main/main.cpp
@@ -30,6 +30,7 @@
 
 #include "main.h"
 
+#include "core/core_string_names.h"
 #include "core/crypto/crypto.h"
 #include "core/debugger/engine_debugger.h"
 #include "core/input/input.h"
@@ -75,12 +76,14 @@
 #include "servers/xr_server.h"
 
 #ifdef TOOLS_ENABLED
+
 #include "editor/doc_data.h"
 #include "editor/doc_data_class_path.gen.h"
 #include "editor/editor_node.h"
 #include "editor/editor_settings.h"
 #include "editor/progress_dialog.h"
 #include "editor/project_manager.h"
+
 #endif
 
 /* Static members */
@@ -186,7 +189,8 @@ static String get_full_version_string() {
 // to have less code in main.cpp.
 void initialize_physics() {
 	/// 3D Physics Server
-	physics_server = PhysicsServer3DManager::new_server(ProjectSettings::get_singleton()->get(PhysicsServer3DManager::setting_property_name));
+	physics_server = PhysicsServer3DManager::new_server(
+			ProjectSettings::get_singleton()->get(PhysicsServer3DManager::setting_property_name));
 	if (!physics_server) {
 		// Physics server not found, Use the default physics
 		physics_server = PhysicsServer3DManager::new_default_server();
@@ -195,7 +199,8 @@ void initialize_physics() {
 	physics_server->init();
 
 	/// 2D Physics server
-	physics_2d_server = PhysicsServer2DManager::new_server(ProjectSettings::get_singleton()->get(PhysicsServer2DManager::setting_property_name));
+	physics_2d_server = PhysicsServer2DManager::new_server(
+			ProjectSettings::get_singleton()->get(PhysicsServer2DManager::setting_property_name));
 	if (!physics_2d_server) {
 		// Physics server not found, Use the default physics
 		physics_2d_server = PhysicsServer2DManager::new_default_server();
@@ -254,20 +259,25 @@ void Main::print_help(const char *p_binary) {
 	OS::get_singleton()->print("  -h, --help                       Display this help message.\n");
 	OS::get_singleton()->print("  --version                        Display the version string.\n");
 	OS::get_singleton()->print("  -v, --verbose                    Use verbose stdout mode.\n");
-	OS::get_singleton()->print("  --quiet                          Quiet mode, silences stdout messages. Errors are still displayed.\n");
+	OS::get_singleton()->print(
+			"  --quiet                          Quiet mode, silences stdout messages. Errors are still displayed.\n");
 	OS::get_singleton()->print("\n");
 
 	OS::get_singleton()->print("Run options:\n");
 #ifdef TOOLS_ENABLED
 	OS::get_singleton()->print("  -e, --editor                     Start the editor instead of running the scene.\n");
-	OS::get_singleton()->print("  -p, --project-manager            Start the project manager, even if a project is auto-detected.\n");
+	OS::get_singleton()->print(
+			"  -p, --project-manager            Start the project manager, even if a project is auto-detected.\n");
 #endif
 	OS::get_singleton()->print("  -q, --quit                       Quit after the first iteration.\n");
-	OS::get_singleton()->print("  -l, --language <locale>          Use a specific locale (<locale> being a two-letter code).\n");
-	OS::get_singleton()->print("  --path <directory>               Path to a project (<directory> must contain a 'project.godot' file).\n");
+	OS::get_singleton()->print(
+			"  -l, --language <locale>          Use a specific locale (<locale> being a two-letter code).\n");
+	OS::get_singleton()->print(
+			"  --path <directory>               Path to a project (<directory> must contain a 'project.godot' file).\n");
 	OS::get_singleton()->print("  -u, --upwards                    Scan folders upwards for project.godot file.\n");
 	OS::get_singleton()->print("  --main-pack <file>               Path to a pack (.pck) file to load.\n");
-	OS::get_singleton()->print("  --render-thread <mode>           Render thread mode ('unsafe', 'safe', 'separate').\n");
+	OS::get_singleton()->print(
+			"  --render-thread <mode>           Render thread mode ('unsafe', 'safe', 'separate').\n");
 	OS::get_singleton()->print("  --remote-fs <address>            Remote filesystem (<host/IP>[:<port>] address).\n");
 	OS::get_singleton()->print("  --remote-fs-password <password>  Password for remote filesystem.\n");
 
@@ -308,9 +318,12 @@ void Main::print_help(const char *p_binary) {
 	OS::get_singleton()->print("  --resolution <W>x<H>             Request window resolution.\n");
 	OS::get_singleton()->print("  --position <X>,<Y>               Request window position.\n");
 	OS::get_singleton()->print("  --low-dpi                        Force low-DPI mode (macOS and Windows only).\n");
-	OS::get_singleton()->print("  --no-window                      Disable window creation (Windows only). Useful together with --script.\n");
-	OS::get_singleton()->print("  --enable-vsync-via-compositor    When vsync is enabled, vsync via the OS' window compositor (Windows only).\n");
-	OS::get_singleton()->print("  --disable-vsync-via-compositor   Disable vsync via the OS' window compositor (Windows only).\n");
+	OS::get_singleton()->print(
+			"  --no-window                      Disable window creation (Windows only). Useful together with --script.\n");
+	OS::get_singleton()->print(
+			"  --enable-vsync-via-compositor    When vsync is enabled, vsync via the OS' window compositor (Windows only).\n");
+	OS::get_singleton()->print(
+			"  --disable-vsync-via-compositor   Disable vsync via the OS' window compositor (Windows only).\n");
 	OS::get_singleton()->print("  --single-window                  Use a single window (no separate subwindows).\n");
 	OS::get_singleton()->print("  --tablet-driver                  Tablet input driver (");
 	for (int i = 0; i < OS::get_singleton()->get_tablet_driver_count(); i++) {
@@ -324,35 +337,51 @@ void Main::print_help(const char *p_binary) {
 
 	OS::get_singleton()->print("Debug options:\n");
 	OS::get_singleton()->print("  -d, --debug                      Debug (local stdout debugger).\n");
-	OS::get_singleton()->print("  -b, --breakpoints                Breakpoint list as source::line comma-separated pairs, no spaces (use %%20 instead).\n");
+	OS::get_singleton()->print(
+			"  -b, --breakpoints                Breakpoint list as source::line comma-separated pairs, no spaces (use %%20 instead).\n");
 	OS::get_singleton()->print("  --profiling                      Enable profiling in the script debugger.\n");
-	OS::get_singleton()->print("  --gpu-abort                      Abort on GPU errors (usually validation layer errors), may help see the problem if your system freezes.\n");
-	OS::get_singleton()->print("  --remote-debug <uri>             Remote debug (<protocol>://<host/IP>[:<port>], e.g. tcp://127.0.0.1:6007).\n");
+	OS::get_singleton()->print(
+			"  --gpu-abort                      Abort on GPU errors (usually validation layer errors), may help see the problem if your system freezes.\n");
+	OS::get_singleton()->print(
+			"  --remote-debug <uri>             Remote debug (<protocol>://<host/IP>[:<port>], e.g. tcp://127.0.0.1:6007).\n");
 #if defined(DEBUG_ENABLED) && !defined(SERVER_ENABLED)
 	OS::get_singleton()->print("  --debug-collisions               Show collision shapes when running the scene.\n");
 	OS::get_singleton()->print("  --debug-navigation               Show navigation polygons when running the scene.\n");
 #endif
-	OS::get_singleton()->print("  --frame-delay <ms>               Simulate high CPU load (delay each frame by <ms> milliseconds).\n");
-	OS::get_singleton()->print("  --time-scale <scale>             Force time scale (higher values are faster, 1.0 is normal speed).\n");
-	OS::get_singleton()->print("  --disable-render-loop            Disable render loop so rendering only occurs when called explicitly from script.\n");
-	OS::get_singleton()->print("  --disable-crash-handler          Disable crash handler when supported by the platform code.\n");
-	OS::get_singleton()->print("  --fixed-fps <fps>                Force a fixed number of frames per second. This setting disables real-time synchronization.\n");
+	OS::get_singleton()->print(
+			"  --frame-delay <ms>               Simulate high CPU load (delay each frame by <ms> milliseconds).\n");
+	OS::get_singleton()->print(
+			"  --time-scale <scale>             Force time scale (higher values are faster, 1.0 is normal speed).\n");
+	OS::get_singleton()->print(
+			"  --disable-render-loop            Disable render loop so rendering only occurs when called explicitly from script.\n");
+	OS::get_singleton()->print(
+			"  --disable-crash-handler          Disable crash handler when supported by the platform code.\n");
+	OS::get_singleton()->print(
+			"  --fixed-fps <fps>                Force a fixed number of frames per second. This setting disables real-time synchronization.\n");
 	OS::get_singleton()->print("  --print-fps                      Print the frames per second to the stdout.\n");
 	OS::get_singleton()->print("\n");
 
 	OS::get_singleton()->print("Standalone tools:\n");
 	OS::get_singleton()->print("  -s, --script <script>            Run a script.\n");
-	OS::get_singleton()->print("  --check-only                     Only parse for errors and quit (use with --script).\n");
+	OS::get_singleton()->print(
+			"  --check-only                     Only parse for errors and quit (use with --script).\n");
 #ifdef TOOLS_ENABLED
-	OS::get_singleton()->print("  --export <preset> <path>         Export the project using the given preset and matching release template. The preset name should match one defined in export_presets.cfg.\n");
-	OS::get_singleton()->print("                                   <path> should be absolute or relative to the project directory, and include the filename for the binary (e.g. 'builds/game.exe'). The target directory should exist.\n");
+	OS::get_singleton()->print(
+			"  --export <preset> <path>         Export the project using the given preset and matching release template. The preset name should match one defined in export_presets.cfg.\n");
+	OS::get_singleton()->print(
+			"                                   <path> should be absolute or relative to the project directory, and include the filename for the binary (e.g. 'builds/game.exe'). The target directory should exist.\n");
 	OS::get_singleton()->print("  --export-debug <preset> <path>   Same as --export, but using the debug template.\n");
-	OS::get_singleton()->print("  --export-pack <preset> <path>    Same as --export, but only export the game pack for the given preset. The <path> extension determines whether it will be in PCK or ZIP format.\n");
-	OS::get_singleton()->print("  --doctool <path>                 Dump the engine API reference to the given <path> in XML format, merging if existing files are found.\n");
-	OS::get_singleton()->print("  --no-docbase                     Disallow dumping the base types (used with --doctool).\n");
-	OS::get_singleton()->print("  --build-solutions                Build the scripting solutions (e.g. for C# projects). Implies --editor and requires a valid project to edit.\n");
+	OS::get_singleton()->print(
+			"  --export-pack <preset> <path>    Same as --export, but only export the game pack for the given preset. The <path> extension determines whether it will be in PCK or ZIP format.\n");
+	OS::get_singleton()->print(
+			"  --doctool <path>                 Dump the engine API reference to the given <path> in XML format, merging if existing files are found.\n");
+	OS::get_singleton()->print(
+			"  --no-docbase                     Disallow dumping the base types (used with --doctool).\n");
+	OS::get_singleton()->print(
+			"  --build-solutions                Build the scripting solutions (e.g. for C# projects). Implies --editor and requires a valid project to edit.\n");
 #ifdef DEBUG_METHODS_ENABLED
-	OS::get_singleton()->print("  --gdnative-generate-json-api     Generate JSON dump of the Godot API for GDNative bindings.\n");
+	OS::get_singleton()->print(
+			"  --gdnative-generate-json-api     Generate JSON dump of the Godot API for GDNative bindings.\n");
 #endif
 	OS::get_singleton()->print("  --test <test>                    Run a unit test [");
 	const char **test_names = tests_get_names();
@@ -366,6 +395,23 @@ void Main::print_help(const char *p_binary) {
 #endif
 }
 
+int Main::test_entrypoint(int argc, char *argv[], bool &tests_need_run) {
+#ifdef TOOLS_ENABLED // templates can't run unit test tool
+	OS::get_singleton()->initialize();
+	StringName::setup();
+	for (int x = 0; x < argc; x++) {
+		if (strncmp(argv[x], "--test", 6)) {
+			tests_need_run = true;
+			return test_main(argc, argv);
+		}
+	}
+	StringName::cleanup();
+	OS::get_singleton()->finalize();
+#endif
+	tests_need_run = false;
+	return 0;
+}
+
 /* Engine initialization
  *
  * Consists of several methods that are called by each platform's specific main(argc, argv).
@@ -418,7 +464,8 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 	ClassDB::register_class<Performance>();
 	engine->add_singleton(Engine::Singleton("Performance", performance));
 
-	GLOBAL_DEF("debug/settings/crash_handler/message", String("Please include this when reporting the bug on https://github.com/godotengine/godot/issues"));
+	GLOBAL_DEF("debug/settings/crash_handler/message",
+			String("Please include this when reporting the bug on https://github.com/godotengine/godot/issues"));
 
 	MAIN_PRINT("Main: Parse CMDLine");
 
@@ -523,7 +570,8 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 				}
 
 				if (!found) {
-					OS::get_singleton()->print("Unknown audio driver '%s', aborting.\nValid options are ", audio_driver.utf8().get_data());
+					OS::get_singleton()->print("Unknown audio driver '%s', aborting.\nValid options are ",
+							audio_driver.utf8().get_data());
 
 					for (int i = 0; i < AudioDriverManager::get_driver_count(); i++) {
 						if (i == AudioDriverManager::get_driver_count() - 1) {
@@ -559,7 +607,8 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 				}
 
 				if (!found) {
-					OS::get_singleton()->print("Unknown display driver '%s', aborting.\nValid options are ", display_driver.utf8().get_data());
+					OS::get_singleton()->print("Unknown display driver '%s', aborting.\nValid options are ",
+							display_driver.utf8().get_data());
 
 					for (int i = 0; i < DisplayServer::get_create_function_count(); i++) {
 						if (i == DisplayServer::get_create_function_count() - 1) {
@@ -607,7 +656,8 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 				}
 
 				if (!found) {
-					OS::get_singleton()->print("Unknown tablet driver '%s', aborting.\n", tablet_driver.utf8().get_data());
+					OS::get_singleton()->print("Unknown tablet driver '%s', aborting.\n",
+							tablet_driver.utf8().get_data());
 					goto error;
 				}
 
@@ -629,7 +679,8 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 
 				if (vm.find("x") == -1) { // invalid parameter format
 
-					OS::get_singleton()->print("Invalid resolution '%s', it should be e.g. '1280x720'.\n", vm.utf8().get_data());
+					OS::get_singleton()->print("Invalid resolution '%s', it should be e.g. '1280x720'.\n",
+							vm.utf8().get_data());
 					goto error;
 				}
 
@@ -637,7 +688,8 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 				int h = vm.get_slice("x", 1).to_int();
 
 				if (w <= 0 || h <= 0) {
-					OS::get_singleton()->print("Invalid resolution '%s', width and height must be above 0.\n", vm.utf8().get_data());
+					OS::get_singleton()->print("Invalid resolution '%s', width and height must be above 0.\n",
+							vm.utf8().get_data());
 					goto error;
 				}
 
@@ -658,7 +710,8 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 
 				if (vm.find(",") == -1) { // invalid parameter format
 
-					OS::get_singleton()->print("Invalid position '%s', it should be e.g. '80,128'.\n", vm.utf8().get_data());
+					OS::get_singleton()->print("Invalid position '%s', it should be e.g. '80,128'.\n",
+							vm.utf8().get_data());
 					goto error;
 				}
 
@@ -754,7 +807,8 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 			// We still pass it to the main arguments since the argument handling itself is not done in this function
 			main_args.push_back(I->get());
 #endif
-		} else if (I->get() == "--export" || I->get() == "--export-debug" || I->get() == "--export-pack") { // Export project
+		} else if (I->get() == "--export" || I->get() == "--export-debug" ||
+				   I->get() == "--export-pack") { // Export project
 
 			editor = true;
 			main_args.push_back(I->get());
@@ -847,7 +901,8 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 			if (I->next()) {
 				debug_uri = I->next()->get();
 				if (debug_uri.find("://") == -1) { // wrong address
-					OS::get_singleton()->print("Invalid debug host address, it should be of the form <protocol>://<host/IP>:<port>.\n");
+					OS::get_singleton()->print(
+							"Invalid debug host address, it should be of the form <protocol>://<host/IP>:<port>.\n");
 					goto error;
 				}
 				N = I->next()->next();
@@ -888,7 +943,8 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 
 #ifdef TOOLS_ENABLED
 	if (editor && project_manager) {
-		OS::get_singleton()->print("Error: Command line arguments implied opening both editor and project manager, which is not possible. Aborting.\n");
+		OS::get_singleton()->print(
+				"Error: Command line arguments implied opening both editor and project manager, which is not possible. Aborting.\n");
 		goto error;
 	}
 #endif
@@ -935,15 +991,35 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 	OS::get_singleton()->ensure_user_data_dir();
 
 	GLOBAL_DEF("memory/limits/multithreaded_server/rid_pool_prealloc", 60);
-	ProjectSettings::get_singleton()->set_custom_property_info("memory/limits/multithreaded_server/rid_pool_prealloc", PropertyInfo(Variant::INT, "memory/limits/multithreaded_server/rid_pool_prealloc", PROPERTY_HINT_RANGE, "0,500,1")); // No negative and limit to 500 due to crashes
+	ProjectSettings::get_singleton()->set_custom_property_info("memory/limits/multithreaded_server/rid_pool_prealloc",
+			PropertyInfo(Variant::INT,
+					"memory/limits/multithreaded_server/rid_pool_prealloc",
+					PROPERTY_HINT_RANGE,
+					"0,500,1")); // No negative and limit to 500 due to crashes
 	GLOBAL_DEF("network/limits/debugger/max_chars_per_second", 32768);
-	ProjectSettings::get_singleton()->set_custom_property_info("network/limits/debugger/max_chars_per_second", PropertyInfo(Variant::INT, "network/limits/debugger/max_chars_per_second", PROPERTY_HINT_RANGE, "0, 4096, 1, or_greater"));
+	ProjectSettings::get_singleton()->set_custom_property_info("network/limits/debugger/max_chars_per_second",
+			PropertyInfo(Variant::INT,
+					"network/limits/debugger/max_chars_per_second",
+					PROPERTY_HINT_RANGE,
+					"0, 4096, 1, or_greater"));
 	GLOBAL_DEF("network/limits/debugger/max_queued_messages", 2048);
-	ProjectSettings::get_singleton()->set_custom_property_info("network/limits/debugger/max_queued_messages", PropertyInfo(Variant::INT, "network/limits/debugger/max_queued_messages", PROPERTY_HINT_RANGE, "0, 8192, 1, or_greater"));
+	ProjectSettings::get_singleton()->set_custom_property_info("network/limits/debugger/max_queued_messages",
+			PropertyInfo(Variant::INT,
+					"network/limits/debugger/max_queued_messages",
+					PROPERTY_HINT_RANGE,
+					"0, 8192, 1, or_greater"));
 	GLOBAL_DEF("network/limits/debugger/max_errors_per_second", 400);
-	ProjectSettings::get_singleton()->set_custom_property_info("network/limits/debugger/max_errors_per_second", PropertyInfo(Variant::INT, "network/limits/debugger/max_errors_per_second", PROPERTY_HINT_RANGE, "0, 200, 1, or_greater"));
+	ProjectSettings::get_singleton()->set_custom_property_info("network/limits/debugger/max_errors_per_second",
+			PropertyInfo(Variant::INT,
+					"network/limits/debugger/max_errors_per_second",
+					PROPERTY_HINT_RANGE,
+					"0, 200, 1, or_greater"));
 	GLOBAL_DEF("network/limits/debugger/max_warnings_per_second", 400);
-	ProjectSettings::get_singleton()->set_custom_property_info("network/limits/debugger/max_warnings_per_second", PropertyInfo(Variant::INT, "network/limits/debugger/max_warnings_per_second", PROPERTY_HINT_RANGE, "0, 200, 1, or_greater"));
+	ProjectSettings::get_singleton()->set_custom_property_info("network/limits/debugger/max_warnings_per_second",
+			PropertyInfo(Variant::INT,
+					"network/limits/debugger/max_warnings_per_second",
+					PROPERTY_HINT_RANGE,
+					"0, 200, 1, or_greater"));
 
 	EngineDebugger::initialize(debug_uri, skip_breakpoints, breakpoints);
 
@@ -978,8 +1054,13 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 	GLOBAL_DEF("logging/file_logging/enable_file_logging.pc", true);
 	GLOBAL_DEF("logging/file_logging/log_path", "user://logs/godot.log");
 	GLOBAL_DEF("logging/file_logging/max_log_files", 5);
-	ProjectSettings::get_singleton()->set_custom_property_info("logging/file_logging/max_log_files", PropertyInfo(Variant::INT, "logging/file_logging/max_log_files", PROPERTY_HINT_RANGE, "0,20,1,or_greater")); //no negative numbers
-	if (!project_manager && !editor && FileAccess::get_create_func(FileAccess::ACCESS_USERDATA) && GLOBAL_GET("logging/file_logging/enable_file_logging")) {
+	ProjectSettings::get_singleton()->set_custom_property_info("logging/file_logging/max_log_files",
+			PropertyInfo(Variant::INT,
+					"logging/file_logging/max_log_files",
+					PROPERTY_HINT_RANGE,
+					"0,20,1,or_greater")); //no negative numbers
+	if (!project_manager && !editor && FileAccess::get_create_func(FileAccess::ACCESS_USERDATA) &&
+			GLOBAL_GET("logging/file_logging/enable_file_logging")) {
 		// Don't create logs for the project manager as they would be written to
 		// the current working directory, which is inconvenient.
 		String base_path = GLOBAL_GET("logging/file_logging/log_path");
@@ -1020,7 +1101,10 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 	OS::get_singleton()->set_cmdline(execpath, main_args);
 
 	GLOBAL_DEF("rendering/quality/driver/driver_name", "Vulkan");
-	ProjectSettings::get_singleton()->set_custom_property_info("rendering/quality/driver/driver_name", PropertyInfo(Variant::STRING, "rendering/quality/driver/driver_name", PROPERTY_HINT_ENUM, "Vulkan,GLES2"));
+	ProjectSettings::get_singleton()->set_custom_property_info("rendering/quality/driver/driver_name",
+			PropertyInfo(Variant::STRING,
+					"rendering/quality/driver/driver_name",
+					PROPERTY_HINT_ENUM, "Vulkan,GLES2"));
 	if (display_driver == "") {
 		display_driver = GLOBAL_GET("rendering/quality/driver/driver_name");
 	}
@@ -1029,24 +1113,39 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 	GLOBAL_DEF("rendering/quality/2d/gles2_use_nvidia_rect_flicker_workaround", false);
 
 	GLOBAL_DEF("display/window/size/width", 1024);
-	ProjectSettings::get_singleton()->set_custom_property_info("display/window/size/width", PropertyInfo(Variant::INT, "display/window/size/width", PROPERTY_HINT_RANGE, "0,7680,or_greater")); // 8K resolution
+	ProjectSettings::get_singleton()->set_custom_property_info("display/window/size/width",
+			PropertyInfo(Variant::INT, "display/window/size/width",
+					PROPERTY_HINT_RANGE,
+					"0,7680,or_greater")); // 8K resolution
 	GLOBAL_DEF("display/window/size/height", 600);
-	ProjectSettings::get_singleton()->set_custom_property_info("display/window/size/height", PropertyInfo(Variant::INT, "display/window/size/height", PROPERTY_HINT_RANGE, "0,4320,or_greater")); // 8K resolution
+	ProjectSettings::get_singleton()->set_custom_property_info("display/window/size/height",
+			PropertyInfo(Variant::INT, "display/window/size/height",
+					PROPERTY_HINT_RANGE,
+					"0,4320,or_greater")); // 8K resolution
 	GLOBAL_DEF("display/window/size/resizable", true);
 	GLOBAL_DEF("display/window/size/borderless", false);
 	GLOBAL_DEF("display/window/size/fullscreen", false);
 	GLOBAL_DEF("display/window/size/always_on_top", false);
 	GLOBAL_DEF("display/window/size/test_width", 0);
-	ProjectSettings::get_singleton()->set_custom_property_info("display/window/size/test_width", PropertyInfo(Variant::INT, "display/window/size/test_width", PROPERTY_HINT_RANGE, "0,7680,or_greater")); // 8K resolution
+	ProjectSettings::get_singleton()->set_custom_property_info("display/window/size/test_width",
+			PropertyInfo(Variant::INT,
+					"display/window/size/test_width",
+					PROPERTY_HINT_RANGE,
+					"0,7680,or_greater")); // 8K resolution
 	GLOBAL_DEF("display/window/size/test_height", 0);
-	ProjectSettings::get_singleton()->set_custom_property_info("display/window/size/test_height", PropertyInfo(Variant::INT, "display/window/size/test_height", PROPERTY_HINT_RANGE, "0,4320,or_greater")); // 8K resolution
+	ProjectSettings::get_singleton()->set_custom_property_info("display/window/size/test_height",
+			PropertyInfo(Variant::INT,
+					"display/window/size/test_height",
+					PROPERTY_HINT_RANGE,
+					"0,4320,or_greater")); // 8K resolution
 
 	if (use_custom_res) {
 		if (!force_res) {
 			window_size.width = GLOBAL_GET("display/window/size/width");
 			window_size.height = GLOBAL_GET("display/window/size/height");
 
-			if (globals->has_setting("display/window/size/test_width") && globals->has_setting("display/window/size/test_height")) {
+			if (globals->has_setting("display/window/size/test_width") &&
+					globals->has_setting("display/window/size/test_height")) {
 				int tw = globals->get("display/window/size/test_width");
 				if (tw > 0) {
 					window_size.width = tw;
@@ -1106,8 +1205,8 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 	}
 
 	/* todo restore
-	OS::get_singleton()->_allow_layered = GLOBAL_DEF("display/window/per_pixel_transparency/allowed", false);
-	video_mode.layered = GLOBAL_DEF("display/window/per_pixel_transparency/enabled", false);
+    OS::get_singleton()->_allow_layered = GLOBAL_DEF("display/window/per_pixel_transparency/allowed", false);
+    video_mode.layered = GLOBAL_DEF("display/window/per_pixel_transparency/enabled", false);
 */
 	GLOBAL_DEF("rendering/quality/intended_usage/framebuffer_allocation", 2);
 	GLOBAL_DEF("rendering/quality/intended_usage/framebuffer_allocation.mobile", 3);
@@ -1180,10 +1279,15 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 	}
 
 	Engine::get_singleton()->set_iterations_per_second(GLOBAL_DEF("physics/common/physics_fps", 60));
-	ProjectSettings::get_singleton()->set_custom_property_info("physics/common/physics_fps", PropertyInfo(Variant::INT, "physics/common/physics_fps", PROPERTY_HINT_RANGE, "1,120,1,or_greater"));
+	ProjectSettings::get_singleton()->set_custom_property_info("physics/common/physics_fps",
+			PropertyInfo(Variant::INT, "physics/common/physics_fps",
+					PROPERTY_HINT_RANGE, "1,120,1,or_greater"));
 	Engine::get_singleton()->set_physics_jitter_fix(GLOBAL_DEF("physics/common/physics_jitter_fix", 0.5));
 	Engine::get_singleton()->set_target_fps(GLOBAL_DEF("debug/settings/fps/force_fps", 0));
-	ProjectSettings::get_singleton()->set_custom_property_info("debug/settings/fps/force_fps", PropertyInfo(Variant::INT, "debug/settings/fps/force_fps", PROPERTY_HINT_RANGE, "0,120,1,or_greater"));
+	ProjectSettings::get_singleton()->set_custom_property_info("debug/settings/fps/force_fps",
+			PropertyInfo(Variant::INT,
+					"debug/settings/fps/force_fps",
+					PROPERTY_HINT_RANGE, "0,120,1,or_greater"));
 
 	GLOBAL_DEF("debug/settings/stdout/print_fps", false);
 	GLOBAL_DEF("debug/settings/stdout/verbose_stdout", false);
@@ -1194,12 +1298,21 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 
 	if (frame_delay == 0) {
 		frame_delay = GLOBAL_DEF("application/run/frame_delay_msec", 0);
-		ProjectSettings::get_singleton()->set_custom_property_info("application/run/frame_delay_msec", PropertyInfo(Variant::INT, "application/run/frame_delay_msec", PROPERTY_HINT_RANGE, "0,100,1,or_greater")); // No negative numbers
+		ProjectSettings::get_singleton()->set_custom_property_info("application/run/frame_delay_msec",
+				PropertyInfo(Variant::INT,
+						"application/run/frame_delay_msec",
+						PROPERTY_HINT_RANGE,
+						"0,100,1,or_greater")); // No negative numbers
 	}
 
 	OS::get_singleton()->set_low_processor_usage_mode(GLOBAL_DEF("application/run/low_processor_mode", false));
-	OS::get_singleton()->set_low_processor_usage_mode_sleep_usec(GLOBAL_DEF("application/run/low_processor_mode_sleep_usec", 6900)); // Roughly 144 FPS
-	ProjectSettings::get_singleton()->set_custom_property_info("application/run/low_processor_mode_sleep_usec", PropertyInfo(Variant::INT, "application/run/low_processor_mode_sleep_usec", PROPERTY_HINT_RANGE, "0,33200,1,or_greater")); // No negative numbers
+	OS::get_singleton()->set_low_processor_usage_mode_sleep_usec(
+			GLOBAL_DEF("application/run/low_processor_mode_sleep_usec", 6900)); // Roughly 144 FPS
+	ProjectSettings::get_singleton()->set_custom_property_info("application/run/low_processor_mode_sleep_usec",
+			PropertyInfo(Variant::INT,
+					"application/run/low_processor_mode_sleep_usec",
+					PROPERTY_HINT_RANGE,
+					"0,33200,1,or_greater")); // No negative numbers
 
 	GLOBAL_DEF("display/window/ios/hide_home_indicator", true);
 
@@ -1286,14 +1399,16 @@ Error Main::setup2(Thread::ID p_main_tid_override) {
 		String rendering_driver; // temp broken
 
 		Error err;
-		display_server = DisplayServer::create(display_driver_idx, rendering_driver, window_mode, window_flags, window_size, err);
+		display_server = DisplayServer::create(display_driver_idx, rendering_driver, window_mode, window_flags,
+				window_size, err);
 		if (err != OK) {
 			//ok i guess we can't use this display server, try other ones
 			for (int i = 0; i < DisplayServer::get_create_function_count(); i++) {
 				if (i == display_driver_idx) {
 					continue; //don't try the same twice
 				}
-				display_server = DisplayServer::create(display_driver_idx, rendering_driver, window_mode, window_flags, window_size, err);
+				display_server = DisplayServer::create(display_driver_idx, rendering_driver, window_mode, window_flags,
+						window_size, err);
 				if (err == OK) {
 					break;
 				}
@@ -1314,7 +1429,9 @@ Error Main::setup2(Thread::ID p_main_tid_override) {
 
 	rendering_server = memnew(RenderingServerRaster);
 	if (OS::get_singleton()->get_render_thread_mode() != OS::RENDER_THREAD_UNSAFE) {
-		rendering_server = memnew(RenderingServerWrapMT(rendering_server, OS::get_singleton()->get_render_thread_mode() == OS::RENDER_SEPARATE_THREAD));
+		rendering_server = memnew(RenderingServerWrapMT(rendering_server,
+				OS::get_singleton()->get_render_thread_mode() ==
+						OS::RENDER_SEPARATE_THREAD));
 	}
 
 	rendering_server->init();
@@ -1379,7 +1496,10 @@ Error Main::setup2(Thread::ID p_main_tid_override) {
 		String boot_logo_path = GLOBAL_DEF("application/boot_splash/image", String());
 		bool boot_logo_scale = GLOBAL_DEF("application/boot_splash/fullsize", true);
 		bool boot_logo_filter = GLOBAL_DEF("application/boot_splash/use_filter", true);
-		ProjectSettings::get_singleton()->set_custom_property_info("application/boot_splash/image", PropertyInfo(Variant::STRING, "application/boot_splash/image", PROPERTY_HINT_FILE, "*.png"));
+		ProjectSettings::get_singleton()->set_custom_property_info("application/boot_splash/image",
+				PropertyInfo(Variant::STRING,
+						"application/boot_splash/image",
+						PROPERTY_HINT_FILE, "*.png"));
 
 		Ref<Image> boot_logo;
 
@@ -1396,7 +1516,8 @@ Error Main::setup2(Thread::ID p_main_tid_override) {
 		Color boot_bg_color = GLOBAL_DEF("application/boot_splash/bg_color", boot_splash_bg_color);
 		if (boot_logo.is_valid()) {
 			OS::get_singleton()->_msec_splash = OS::get_singleton()->get_ticks_msec();
-			RenderingServer::get_singleton()->set_boot_image(boot_logo, boot_bg_color, boot_logo_scale, boot_logo_filter);
+			RenderingServer::get_singleton()->set_boot_image(boot_logo, boot_bg_color, boot_logo_scale,
+					boot_logo_filter);
 
 		} else {
 #ifndef NO_DEFAULT_BOOT_LOGO
@@ -1421,21 +1542,31 @@ Error Main::setup2(Thread::ID p_main_tid_override) {
 	}
 
 	MAIN_PRINT("Main: DCC");
-	RenderingServer::get_singleton()->set_default_clear_color(GLOBAL_DEF("rendering/environment/default_clear_color", Color(0.3, 0.3, 0.3)));
+	RenderingServer::get_singleton()->set_default_clear_color(
+			GLOBAL_DEF("rendering/environment/default_clear_color", Color(0.3, 0.3, 0.3)));
 	MAIN_PRINT("Main: END");
 
 	GLOBAL_DEF("application/config/icon", String());
-	ProjectSettings::get_singleton()->set_custom_property_info("application/config/icon", PropertyInfo(Variant::STRING, "application/config/icon", PROPERTY_HINT_FILE, "*.png,*.webp"));
+	ProjectSettings::get_singleton()->set_custom_property_info("application/config/icon",
+			PropertyInfo(Variant::STRING, "application/config/icon",
+					PROPERTY_HINT_FILE, "*.png,*.webp"));
 
 	GLOBAL_DEF("application/config/macos_native_icon", String());
-	ProjectSettings::get_singleton()->set_custom_property_info("application/config/macos_native_icon", PropertyInfo(Variant::STRING, "application/config/macos_native_icon", PROPERTY_HINT_FILE, "*.icns"));
+	ProjectSettings::get_singleton()->set_custom_property_info("application/config/macos_native_icon",
+			PropertyInfo(Variant::STRING,
+					"application/config/macos_native_icon",
+					PROPERTY_HINT_FILE, "*.icns"));
 
 	GLOBAL_DEF("application/config/windows_native_icon", String());
-	ProjectSettings::get_singleton()->set_custom_property_info("application/config/windows_native_icon", PropertyInfo(Variant::STRING, "application/config/windows_native_icon", PROPERTY_HINT_FILE, "*.ico"));
+	ProjectSettings::get_singleton()->set_custom_property_info("application/config/windows_native_icon",
+			PropertyInfo(Variant::STRING,
+					"application/config/windows_native_icon",
+					PROPERTY_HINT_FILE, "*.ico"));
 
 	Input *id = Input::get_singleton();
 	if (id) {
-		if (bool(GLOBAL_DEF("input_devices/pointing/emulate_touch_from_mouse", false)) && !(editor || project_manager)) {
+		if (bool(GLOBAL_DEF("input_devices/pointing/emulate_touch_from_mouse", false)) &&
+				!(editor || project_manager)) {
 			bool found_touchscreen = false;
 			for (int i = 0; i < DisplayServer::get_singleton()->get_screen_count(); i++) {
 				if (DisplayServer::get_singleton()->screen_is_touchscreen(i)) {
@@ -1460,10 +1591,14 @@ Error Main::setup2(Thread::ID p_main_tid_override) {
 	GLOBAL_DEF("display/mouse_cursor/custom_image", String());
 	GLOBAL_DEF("display/mouse_cursor/custom_image_hotspot", Vector2());
 	GLOBAL_DEF("display/mouse_cursor/tooltip_position_offset", Point2(10, 10));
-	ProjectSettings::get_singleton()->set_custom_property_info("display/mouse_cursor/custom_image", PropertyInfo(Variant::STRING, "display/mouse_cursor/custom_image", PROPERTY_HINT_FILE, "*.png,*.webp"));
+	ProjectSettings::get_singleton()->set_custom_property_info("display/mouse_cursor/custom_image",
+			PropertyInfo(Variant::STRING,
+					"display/mouse_cursor/custom_image",
+					PROPERTY_HINT_FILE, "*.png,*.webp"));
 
 	if (String(ProjectSettings::get_singleton()->get("display/mouse_cursor/custom_image")) != String()) {
-		Ref<Texture2D> cursor = ResourceLoader::load(ProjectSettings::get_singleton()->get("display/mouse_cursor/custom_image"));
+		Ref<Texture2D> cursor = ResourceLoader::load(
+				ProjectSettings::get_singleton()->get("display/mouse_cursor/custom_image"));
 		if (cursor.is_valid()) {
 			Vector2 hotspot = ProjectSettings::get_singleton()->get("display/mouse_cursor/custom_image_hotspot");
 			Input::get_singleton()->set_custom_mouse_cursor(cursor, Input::CURSOR_ARROW, hotspot);
@@ -1544,7 +1679,6 @@ bool Main::start() {
 	String positional_arg;
 	String game_path;
 	String script;
-	String test;
 	bool check_only = false;
 
 #ifdef TOOLS_ENABLED
@@ -1555,10 +1689,12 @@ bool Main::start() {
 #endif
 
 	main_timer_sync.init(OS::get_singleton()->get_ticks_usec());
-
 	List<String> args = OS::get_singleton()->get_cmdline_args();
+
+	// parameters that do not have an argument to the right
 	for (int i = 0; i < args.size(); i++) {
-		//parameters that do not have an argument to the right
+		// Doctest Unit Testing Handler
+		// Designed to override and pass arguments to the unit test handler.
 		if (args[i] == "--check-only") {
 			check_only = true;
 #ifdef TOOLS_ENABLED
@@ -1591,8 +1727,6 @@ bool Main::start() {
 			bool parsed_pair = true;
 			if (args[i] == "-s" || args[i] == "--script") {
 				script = args[i + 1];
-			} else if (args[i] == "--test") {
-				test = args[i + 1];
 #ifdef TOOLS_ENABLED
 			} else if (args[i] == "--doctool") {
 				doc_tool = args[i + 1];
@@ -1624,7 +1758,8 @@ bool Main::start() {
 	String main_loop_type;
 #ifdef TOOLS_ENABLED
 	if (doc_tool != "") {
-		Engine::get_singleton()->set_editor_hint(true); // Needed to instance editor-only classes for their default values
+		Engine::get_singleton()->set_editor_hint(
+				true); // Needed to instance editor-only classes for their default values
 
 		{
 			DirAccessRef da = DirAccess::open(doc_tool);
@@ -1694,7 +1829,7 @@ bool Main::start() {
 		print_line("Generating new docs...");
 		doc.save_classes(index_path, doc_data_classes);
 
-		return false;
+		return FAILED;
 	}
 
 	if (_export_preset != "") {
@@ -1702,7 +1837,7 @@ bool Main::start() {
 			String err = "Command line includes export parameter option, but no destination path was given.\n";
 			err += "Please specify the binary's file path to export to. Aborting export.";
 			ERR_PRINT(err);
-			return false;
+			return FAILED;
 		}
 	}
 #endif
@@ -1716,16 +1851,7 @@ bool Main::start() {
 		main_loop = memnew(SceneTree);
 	};
 
-	if (test != "") {
-#ifdef TOOLS_ENABLED
-		main_loop = test_main(test, args);
-
-		if (!main_loop) {
-			return false;
-		}
-#endif
-
-	} else if (script != "") {
+	if (script != "") {
 		Ref<Script> script_res = ResourceLoader::load(script);
 		ERR_FAIL_COND_V_MSG(script_res.is_null(), false, "Can't load script: " + script);
 
@@ -1733,7 +1859,7 @@ bool Main::start() {
 			if (!script_res->is_valid()) {
 				OS::get_singleton()->set_exit_code(1);
 			}
-			return false;
+			return FAILED;
 		}
 
 		if (script_res->can_instance()) {
@@ -1744,13 +1870,15 @@ bool Main::start() {
 				if (obj) {
 					memdelete(obj);
 				}
-				ERR_FAIL_V_MSG(false, vformat("Can't load the script \"%s\" as it doesn't inherit from SceneTree or MainLoop.", script));
+				ERR_FAIL_V_MSG(false,
+						vformat("Can't load the script \"%s\" as it doesn't inherit from SceneTree or MainLoop.",
+								script));
 			}
 
 			script_loop->set_init_script(script_res);
 			main_loop = script_loop;
 		} else {
-			return false;
+			return FAILED;
 		}
 
 	} else {
@@ -1764,7 +1892,7 @@ bool Main::start() {
 	if (!main_loop) {
 		if (!ClassDB::class_exists(main_loop_type)) {
 			DisplayServer::get_singleton()->alert("Error: MainLoop type doesn't exist: " + main_loop_type);
-			return false;
+			return FAILED;
 		} else {
 			Object *ml = ClassDB::instance(main_loop_type);
 			ERR_FAIL_COND_V_MSG(!ml, false, "Can't instance MainLoop type.");
@@ -1832,7 +1960,9 @@ bool Main::start() {
 
 						Object *obj = ClassDB::instance(ibt);
 
-						ERR_CONTINUE_MSG(obj == nullptr, "Cannot instance script for autoload, expected 'Node' inheritance, got: " + String(ibt));
+						ERR_CONTINUE_MSG(obj == nullptr,
+								"Cannot instance script for autoload, expected 'Node' inheritance, got: " +
+										String(ibt));
 
 						n = Object::cast_to<Node>(obj);
 						n->set_script(script_res);
@@ -1880,7 +2010,8 @@ bool Main::start() {
 
 			String stretch_mode = GLOBAL_DEF("display/window/stretch/mode", "disabled");
 			String stretch_aspect = GLOBAL_DEF("display/window/stretch/aspect", "ignore");
-			Size2i stretch_size = Size2(GLOBAL_DEF("display/window/size/width", 0), GLOBAL_DEF("display/window/size/height", 0));
+			Size2i stretch_size = Size2(GLOBAL_DEF("display/window/size/width", 0),
+					GLOBAL_DEF("display/window/size/height", 0));
 
 			Window::ContentScaleMode cs_sm = Window::CONTENT_SCALE_MODE_DISABLED;
 			if (stretch_mode == "canvas_items") {
@@ -1924,10 +2055,14 @@ bool Main::start() {
 			int shadow_atlas_q3_subdiv = GLOBAL_GET("rendering/quality/shadow_atlas/quadrant_3_subdiv");
 
 			sml->get_root()->set_shadow_atlas_size(shadow_atlas_size);
-			sml->get_root()->set_shadow_atlas_quadrant_subdiv(0, Viewport::ShadowAtlasQuadrantSubdiv(shadow_atlas_q0_subdiv));
-			sml->get_root()->set_shadow_atlas_quadrant_subdiv(1, Viewport::ShadowAtlasQuadrantSubdiv(shadow_atlas_q1_subdiv));
-			sml->get_root()->set_shadow_atlas_quadrant_subdiv(2, Viewport::ShadowAtlasQuadrantSubdiv(shadow_atlas_q2_subdiv));
-			sml->get_root()->set_shadow_atlas_quadrant_subdiv(3, Viewport::ShadowAtlasQuadrantSubdiv(shadow_atlas_q3_subdiv));
+			sml->get_root()->set_shadow_atlas_quadrant_subdiv(0, Viewport::ShadowAtlasQuadrantSubdiv(
+																		 shadow_atlas_q0_subdiv));
+			sml->get_root()->set_shadow_atlas_quadrant_subdiv(1, Viewport::ShadowAtlasQuadrantSubdiv(
+																		 shadow_atlas_q1_subdiv));
+			sml->get_root()->set_shadow_atlas_quadrant_subdiv(2, Viewport::ShadowAtlasQuadrantSubdiv(
+																		 shadow_atlas_q2_subdiv));
+			sml->get_root()->set_shadow_atlas_quadrant_subdiv(3, Viewport::ShadowAtlasQuadrantSubdiv(
+																		 shadow_atlas_q3_subdiv));
 
 			bool snap_controls = GLOBAL_DEF("gui/common/snap_controls_to_pixels", true);
 			sml->get_root()->set_snap_controls_to_pixels(snap_controls);
@@ -1937,30 +2072,51 @@ bool Main::start() {
 
 			int texture_filter = GLOBAL_DEF("rendering/canvas_textures/default_texture_filter", 1);
 			int texture_repeat = GLOBAL_DEF("rendering/canvas_textures/default_texture_repeat", 0);
-			sml->get_root()->set_default_canvas_item_texture_filter(Viewport::DefaultCanvasItemTextureFilter(texture_filter));
-			sml->get_root()->set_default_canvas_item_texture_repeat(Viewport::DefaultCanvasItemTextureRepeat(texture_repeat));
+			sml->get_root()->set_default_canvas_item_texture_filter(
+					Viewport::DefaultCanvasItemTextureFilter(texture_filter));
+			sml->get_root()->set_default_canvas_item_texture_repeat(
+					Viewport::DefaultCanvasItemTextureRepeat(texture_repeat));
 
 		} else {
 			GLOBAL_DEF("display/window/stretch/mode", "disabled");
-			ProjectSettings::get_singleton()->set_custom_property_info("display/window/stretch/mode", PropertyInfo(Variant::STRING, "display/window/stretch/mode", PROPERTY_HINT_ENUM, "disabled,canvas_items,viewport"));
+			ProjectSettings::get_singleton()->set_custom_property_info("display/window/stretch/mode",
+					PropertyInfo(Variant::STRING,
+							"display/window/stretch/mode",
+							PROPERTY_HINT_ENUM,
+							"disabled,canvas_items,viewport"));
 			GLOBAL_DEF("display/window/stretch/aspect", "ignore");
-			ProjectSettings::get_singleton()->set_custom_property_info("display/window/stretch/aspect", PropertyInfo(Variant::STRING, "display/window/stretch/aspect", PROPERTY_HINT_ENUM, "ignore,keep,keep_width,keep_height,expand"));
+			ProjectSettings::get_singleton()->set_custom_property_info("display/window/stretch/aspect",
+					PropertyInfo(Variant::STRING,
+							"display/window/stretch/aspect",
+							PROPERTY_HINT_ENUM,
+							"ignore,keep,keep_width,keep_height,expand"));
 			GLOBAL_DEF("display/window/stretch/shrink", 1.0);
-			ProjectSettings::get_singleton()->set_custom_property_info("display/window/stretch/shrink", PropertyInfo(Variant::FLOAT, "display/window/stretch/shrink", PROPERTY_HINT_RANGE, "1.0,8.0,0.1"));
+			ProjectSettings::get_singleton()->set_custom_property_info("display/window/stretch/shrink",
+					PropertyInfo(Variant::FLOAT,
+							"display/window/stretch/shrink",
+							PROPERTY_HINT_RANGE,
+							"1.0,8.0,0.1"));
 			sml->set_auto_accept_quit(GLOBAL_DEF("application/config/auto_accept_quit", true));
 			sml->set_quit_on_go_back(GLOBAL_DEF("application/config/quit_on_go_back", true));
 			GLOBAL_DEF("gui/common/snap_controls_to_pixels", true);
 			GLOBAL_DEF("rendering/quality/dynamic_fonts/use_oversampling", true);
 
 			GLOBAL_DEF("rendering/canvas_textures/default_texture_filter", 1);
-			ProjectSettings::get_singleton()->set_custom_property_info("rendering/canvas_textures/default_texture_filter", PropertyInfo(Variant::INT, "rendering/canvas_textures/default_texture_filter", PROPERTY_HINT_ENUM, "Nearest,Linear,MipmapLinear,MipmapNearest"));
+			ProjectSettings::get_singleton()->set_custom_property_info(
+					"rendering/canvas_textures/default_texture_filter",
+					PropertyInfo(Variant::INT, "rendering/canvas_textures/default_texture_filter", PROPERTY_HINT_ENUM,
+							"Nearest,Linear,MipmapLinear,MipmapNearest"));
 			GLOBAL_DEF("rendering/canvas_textures/default_texture_repeat", 0);
-			ProjectSettings::get_singleton()->set_custom_property_info("rendering/canvas_textures/default_texture_repeat", PropertyInfo(Variant::INT, "rendering/canvas_textures/default_texture_repeat", PROPERTY_HINT_ENUM, "Disable,Enable,Mirror"));
+			ProjectSettings::get_singleton()->set_custom_property_info(
+					"rendering/canvas_textures/default_texture_repeat",
+					PropertyInfo(Variant::INT, "rendering/canvas_textures/default_texture_repeat", PROPERTY_HINT_ENUM,
+							"Disable,Enable,Mirror"));
 		}
 
 #ifdef TOOLS_ENABLED
 		if (editor) {
-			bool editor_embed_subwindows = EditorSettings::get_singleton()->get_setting("interface/editor/single_window_mode");
+			bool editor_embed_subwindows = EditorSettings::get_singleton()->get_setting(
+					"interface/editor/single_window_mode");
 
 			if (editor_embed_subwindows) {
 				sml->get_root()->set_embed_subwindows_hint(true);
@@ -1973,7 +2129,8 @@ bool Main::start() {
 			local_game_path = game_path.replace("\\", "/");
 
 			if (!local_game_path.begins_with("res://")) {
-				bool absolute = (local_game_path.size() > 1) && (local_game_path[0] == '/' || local_game_path[1] == ':');
+				bool absolute =
+						(local_game_path.size() > 1) && (local_game_path[0] == '/' || local_game_path[1] == ':');
 
 				if (!absolute) {
 					if (ProjectSettings::get_singleton()->is_using_datapack()) {
@@ -1989,7 +2146,8 @@ bool Main::start() {
 						} else {
 							DirAccess *da = DirAccess::open(local_game_path.substr(0, sep));
 							if (da) {
-								local_game_path = da->get_current_dir().plus_file(local_game_path.substr(sep + 1, local_game_path.length()));
+								local_game_path = da->get_current_dir().plus_file(
+										local_game_path.substr(sep + 1, local_game_path.length()));
 								memdelete(da);
 							}
 						}
@@ -2059,7 +2217,7 @@ bool Main::start() {
 		}
 
 #ifdef TOOLS_ENABLED
-		if (project_manager || (script == "" && test == "" && game_path == "" && !editor)) {
+		if (project_manager || (script == "" && game_path == "" && !editor)) {
 			Engine::get_singleton()->set_editor_hint(true);
 			ProjectManager *pmanager = memnew(ProjectManager);
 			ProgressDialog *progress_dialog = memnew(ProgressDialog);
@@ -2072,12 +2230,16 @@ bool Main::start() {
 		if (project_manager || editor) {
 			if (DisplayServer::get_singleton()->has_feature(DisplayServer::FEATURE_CONSOLE_WINDOW)) {
 				// Hide console window if requested (Windows-only).
-				bool hide_console = EditorSettings::get_singleton()->get_setting("interface/editor/hide_console_window");
+				bool hide_console = EditorSettings::get_singleton()->get_setting(
+						"interface/editor/hide_console_window");
 				DisplayServer::get_singleton()->console_set_visible(!hide_console);
 			}
 
 			// Load SSL Certificates from Editor Settings (or builtin)
-			Crypto::load_default_certificates(EditorSettings::get_singleton()->get_setting("network/ssl/editor_ssl_certificates").operator String());
+			Crypto::load_default_certificates(EditorSettings::get_singleton()->get_setting(
+																					 "network/ssl/editor_ssl_certificates")
+													  .
+													  operator String());
 		}
 #endif
 	}
@@ -2089,7 +2251,7 @@ bool Main::start() {
 
 	OS::get_singleton()->set_main_loop(main_loop);
 
-	return true;
+	return OK;
 }
 
 /* Main iteration
@@ -2107,6 +2269,7 @@ uint32_t Main::frames = 0;
 uint32_t Main::frame = 0;
 bool Main::force_redraw_requested = false;
 int Main::iterating = 0;
+
 bool Main::is_iterating() {
 	return iterating > 0;
 }
@@ -2182,7 +2345,8 @@ bool Main::iteration() {
 
 		message_queue->flush();
 
-		physics_process_ticks = MAX(physics_process_ticks, OS::get_singleton()->get_ticks_usec() - physics_begin); // keep the largest one for reference
+		physics_process_ticks = MAX(physics_process_ticks, OS::get_singleton()->get_ticks_usec() -
+																   physics_begin); // keep the largest one for reference
 		physics_process_max = MAX(OS::get_singleton()->get_ticks_usec() - physics_begin, physics_process_max);
 		Engine::get_singleton()->_physics_frames++;
 	}
@@ -2198,7 +2362,8 @@ bool Main::iteration() {
 
 	RenderingServer::get_singleton()->sync(); //sync if still drawing from previous frames.
 
-	if (DisplayServer::get_singleton()->can_any_window_draw() && RenderingServer::get_singleton()->is_render_loop_enabled()) {
+	if (DisplayServer::get_singleton()->can_any_window_draw() &&
+			RenderingServer::get_singleton()->is_render_loop_enabled()) {
 		if ((!force_redraw_requested) && OS::get_singleton()->is_in_low_processor_usage_mode()) {
 			if (RenderingServer::get_singleton()->has_changed()) {
 				RenderingServer::get_singleton()->draw(true, scaled_step); // flush visual commands
@@ -2260,10 +2425,12 @@ bool Main::iteration() {
 		auto_build_solutions = false;
 		// Only relevant when running the editor.
 		if (!editor) {
-			ERR_FAIL_V_MSG(true, "Command line option --build-solutions was passed, but no project is being edited. Aborting.");
+			ERR_FAIL_V_MSG(true,
+					"Command line option --build-solutions was passed, but no project is being edited. Aborting.");
 		}
 		if (!EditorNode::get_singleton()->call_build()) {
-			ERR_FAIL_V_MSG(true, "Command line option --build-solutions was passed, but the build callback failed. Aborting.");
+			ERR_FAIL_V_MSG(true,
+					"Command line option --build-solutions was passed, but the build callback failed. Aborting.");
 		}
 	}
 #endif
diff --git a/main/main.h b/main/main.h
index 308128735c..20c0bebefa 100644
--- a/main/main.h
+++ b/main/main.h
@@ -45,7 +45,7 @@ class Main {
 
 public:
 	static bool is_project_manager();
-
+	static int test_entrypoint(int argc, char *argv[], bool &tests_need_run);
 	static Error setup(const char *execpath, int argc, char *argv[], bool p_second_phase = true);
 	static Error setup2(Thread::ID p_main_tid_override = 0);
 	static bool start();
@@ -58,4 +58,19 @@ public:
 	static void cleanup();
 };
 
+// Test main override is for the testing behaviour
+#define TEST_MAIN_OVERRIDE                                         \
+	bool run_test = false;                                         \
+	int return_code = Main::test_entrypoint(argc, argv, run_test); \
+	if (run_test) {                                                \
+		return return_code;                                        \
+	}
+
+#define TEST_MAIN_PARAM_OVERRIDE(argc, argv)                       \
+	bool run_test = false;                                         \
+	int return_code = Main::test_entrypoint(argc, argv, run_test); \
+	if (run_test) {                                                \
+		return return_code;                                        \
+	}
+
 #endif // MAIN_H
diff --git a/main/tests/test_main.cpp b/main/tests/test_main.cpp
index 5ebdaf1741..91eff28f86 100644
--- a/main/tests/test_main.cpp
+++ b/main/tests/test_main.cpp
@@ -47,10 +47,14 @@
 #include "test_render.h"
 #include "test_shader_lang.h"
 #include "test_string.h"
+#include "test_validate_testing.h"
+
+#include "thirdparty/doctest/doctest.h"
 
 const char **tests_get_names() {
 	static const char *test_names[] = {
-		"string",
+		"*",
+		"all",
 		"math",
 		"basis",
 		"physics_2d",
@@ -72,75 +76,38 @@ const char **tests_get_names() {
 	return test_names;
 }
 
-MainLoop *test_main(String p_test, const List<String> &p_args) {
-	if (p_test == "string") {
-		return TestString::test();
-	}
-
-	if (p_test == "math") {
-		return TestMath::test();
-	}
-
-	if (p_test == "basis") {
-		return TestBasis::test();
-	}
-
-	if (p_test == "physics_2d") {
-		return TestPhysics2D::test();
-	}
-
-	if (p_test == "physics_3d") {
-		return TestPhysics3D::test();
-	}
-
-	if (p_test == "render") {
-		return TestRender::test();
-	}
-
-	if (p_test == "oa_hash_map") {
-		return TestOAHashMap::test();
-	}
-
-	if (p_test == "class_db") {
-		return TestClassDB::test();
-	}
-
-#ifndef _3D_DISABLED
-	if (p_test == "gui") {
-		return TestGUI::test();
-	}
-#endif
-
-	if (p_test == "shaderlang") {
-		return TestShaderLang::test();
-	}
-
-	if (p_test == "gd_tokenizer") {
-		return TestGDScript::test(TestGDScript::TEST_TOKENIZER);
-	}
-
-	if (p_test == "gd_parser") {
-		return TestGDScript::test(TestGDScript::TEST_PARSER);
-	}
-
-	if (p_test == "gd_compiler") {
-		return TestGDScript::test(TestGDScript::TEST_COMPILER);
-	}
-
-	if (p_test == "gd_bytecode") {
-		return TestGDScript::test(TestGDScript::TEST_BYTECODE);
-	}
-
-	if (p_test == "ordered_hash_map") {
-		return TestOrderedHashMap::test();
-	}
-
-	if (p_test == "astar") {
-		return TestAStar::test();
-	}
-
-	print_line("Unknown test: " + p_test);
-	return nullptr;
+int test_main(int argc, char *argv[]) {
+	// doctest runner for when legacy unit tests are no  found
+	doctest::Context test_context;
+	List<String> valid_arguments;
+
+	// clean arguments of --test from the args
+	int argument_count = 0;
+	for (int x = 0; x < argc; x++) {
+		if (strncmp(argv[x], "--test", 6) != 0) {
+			valid_arguments.push_back(String(argv[x]));
+			argument_count++;
+		}
+	}
+
+	// convert godot command line arguments back to standard arguments.
+	char **args = new char *[valid_arguments.size()];
+	for (int x = 0; x < valid_arguments.size(); x++) {
+		// operation to convert godot string to non wchar string
+		const char *str = valid_arguments[x].utf8().ptr();
+		// allocate the string copy
+		args[x] = new char[strlen(str) + 1];
+		// copy this into memory
+		std::memcpy(args[x], str, strlen(str) + 1);
+	}
+
+	test_context.applyCommandLine(valid_arguments.size(), args);
+
+	test_context.setOption("order-by", "name");
+	test_context.setOption("abort-after", 5);
+	test_context.setOption("no-breaks", true);
+	delete[] args;
+	return test_context.run();
 }
 
 #else
@@ -153,8 +120,8 @@ const char **tests_get_names() {
 	return test_names;
 }
 
-MainLoop *test_main(String p_test, const List<String> &p_args) {
-	return nullptr;
+int test_main(int argc, char *argv[]) {
+	return 0;
 }
 
 #endif
diff --git a/main/tests/test_main.h b/main/tests/test_main.h
index bdb1668d21..8273b74eac 100644
--- a/main/tests/test_main.h
+++ b/main/tests/test_main.h
@@ -36,6 +36,6 @@
 #include "core/ustring.h"
 
 const char **tests_get_names();
-MainLoop *test_main(String p_test, const List<String> &p_args);
+int test_main(int argc, char *argv[]);
 
 #endif // TEST_MAIN_H
diff --git a/main/tests/test_string.cpp b/main/tests/test_string.cpp
deleted file mode 100644
index 73d59b0088..0000000000
--- a/main/tests/test_string.cpp
+++ /dev/null
@@ -1,1207 +0,0 @@
-/*************************************************************************/
-/*  test_string.cpp                                                      */
-/*************************************************************************/
-/*                       This file is part of:                           */
-/*                           GODOT ENGINE                                */
-/*                      https://godotengine.org                          */
-/*************************************************************************/
-/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
-/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
-/*                                                                       */
-/* Permission is hereby granted, free of charge, to any person obtaining */
-/* a copy of this software and associated documentation files (the       */
-/* "Software"), to deal in the Software without restriction, including   */
-/* without limitation the rights to use, copy, modify, merge, publish,   */
-/* distribute, sublicense, and/or sell copies of the Software, and to    */
-/* permit persons to whom the Software is furnished to do so, subject to */
-/* the following conditions:                                             */
-/*                                                                       */
-/* The above copyright notice and this permission notice shall be        */
-/* included in all copies or substantial portions of the Software.       */
-/*                                                                       */
-/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
-/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
-/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
-/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
-/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
-/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
-/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
-/*************************************************************************/
-
-#include "test_string.h"
-
-#include "core/io/ip_address.h"
-#include "core/os/os.h"
-#include "core/ustring.h"
-
-#include "modules/modules_enabled.gen.h"
-#ifdef MODULE_REGEX_ENABLED
-#include "modules/regex/regex.h"
-#endif
-
-#include <stdio.h>
-#include <wchar.h>
-
-namespace TestString {
-
-bool test_1() {
-	OS::get_singleton()->print("\n\nTest 1: Assign from cstr\n");
-
-	String s = "Hello";
-
-	OS::get_singleton()->print("\tExpected: Hello\n");
-	OS::get_singleton()->print("\tResulted: %ls\n", s.c_str());
-
-	return (wcscmp(s.c_str(), L"Hello") == 0);
-}
-
-bool test_2() {
-	OS::get_singleton()->print("\n\nTest 2: Assign from string (operator=)\n");
-
-	String s = "Dolly";
-	const String &t = s;
-
-	OS::get_singleton()->print("\tExpected: Dolly\n");
-	OS::get_singleton()->print("\tResulted: %ls\n", t.c_str());
-
-	return (wcscmp(t.c_str(), L"Dolly") == 0);
-}
-
-bool test_3() {
-	OS::get_singleton()->print("\n\nTest 3: Assign from c-string (copycon)\n");
-
-	String s("Sheep");
-	const String &t(s);
-
-	OS::get_singleton()->print("\tExpected: Sheep\n");
-	OS::get_singleton()->print("\tResulted: %ls\n", t.c_str());
-
-	return (wcscmp(t.c_str(), L"Sheep") == 0);
-}
-
-bool test_4() {
-	OS::get_singleton()->print("\n\nTest 4: Assign from c-widechar (operator=)\n");
-
-	String s(L"Give me");
-
-	OS::get_singleton()->print("\tExpected: Give me\n");
-	OS::get_singleton()->print("\tResulted: %ls\n", s.c_str());
-
-	return (wcscmp(s.c_str(), L"Give me") == 0);
-}
-
-bool test_5() {
-	OS::get_singleton()->print("\n\nTest 5: Assign from c-widechar (copycon)\n");
-
-	String s(L"Wool");
-
-	OS::get_singleton()->print("\tExpected: Wool\n");
-	OS::get_singleton()->print("\tResulted: %ls\n", s.c_str());
-
-	return (wcscmp(s.c_str(), L"Wool") == 0);
-}
-
-bool test_6() {
-	OS::get_singleton()->print("\n\nTest 6: comparisons (equal)\n");
-
-	String s = "Test Compare";
-
-	OS::get_singleton()->print("\tComparing to \"Test Compare\"\n");
-
-	if (!(s == "Test Compare")) {
-		return false;
-	}
-
-	if (!(s == L"Test Compare")) {
-		return false;
-	}
-
-	if (!(s == String("Test Compare"))) {
-		return false;
-	}
-
-	return true;
-}
-
-bool test_7() {
-	OS::get_singleton()->print("\n\nTest 7: comparisons (unequal)\n");
-
-	String s = "Test Compare";
-
-	OS::get_singleton()->print("\tComparing to \"Test Compare\"\n");
-
-	if (!(s != "Peanut")) {
-		return false;
-	}
-
-	if (!(s != L"Coconut")) {
-		return false;
-	}
-
-	if (!(s != String("Butter"))) {
-		return false;
-	}
-
-	return true;
-}
-
-bool test_8() {
-	OS::get_singleton()->print("\n\nTest 8: comparisons (operator<)\n");
-
-	String s = "Bees";
-
-	OS::get_singleton()->print("\tComparing to \"Bees\"\n");
-
-	if (!(s < "Elephant")) {
-		return false;
-	}
-
-	if (s < L"Amber") {
-		return false;
-	}
-
-	if (s < String("Beatrix")) {
-		return false;
-	}
-
-	return true;
-}
-
-bool test_9() {
-	OS::get_singleton()->print("\n\nTest 9: Concatenation\n");
-
-	String s;
-
-	s += "Have";
-	s += ' ';
-	s += 'a';
-	s += String(" ");
-	s = s + L"Nice";
-	s = s + " ";
-	s = s + String("Day");
-
-	OS::get_singleton()->print("\tComparing to \"Have a Nice Day\"\n");
-
-	return (s == "Have a Nice Day");
-}
-
-bool test_10() {
-	OS::get_singleton()->print("\n\nTest 10: Misc funcs (size/length/empty/etc)\n");
-
-	if (!String("").empty()) {
-		return false;
-	}
-
-	if (String("Mellon").size() != 7) {
-		return false;
-	}
-
-	if (String("Oranges").length() != 7) {
-		return false;
-	}
-
-	return true;
-}
-
-bool test_11() {
-	OS::get_singleton()->print("\n\nTest 11: Operator[]\n");
-
-	String a = "Kugar Sane";
-
-	a[0] = 'S';
-	a[6] = 'C';
-
-	if (a != "Sugar Cane") {
-		return false;
-	}
-
-	if (a[1] != 'u') {
-		return false;
-	}
-
-	return true;
-}
-
-bool test_12() {
-	OS::get_singleton()->print("\n\nTest 12: case functions\n");
-
-	String a = "MoMoNgA";
-
-	if (a.to_upper() != "MOMONGA") {
-		return false;
-	}
-
-	if (a.nocasecmp_to("momonga") != 0) {
-		return false;
-	}
-
-	return true;
-}
-
-bool test_13() {
-	OS::get_singleton()->print("\n\nTest 13: UTF8\n");
-
-	/* how can i embed UTF in here? */
-
-	static const CharType ustr[] = { 0x304A, 0x360F, 0x3088, 0x3046, 0 };
-	//static const wchar_t ustr[] = { 'P', 0xCE, 'p',0xD3, 0 };
-	String s = ustr;
-
-	OS::get_singleton()->print("\tUnicode: %ls\n", ustr);
-	s.parse_utf8(s.utf8().get_data());
-	OS::get_singleton()->print("\tConvert/Parse UTF8: %ls\n", s.c_str());
-
-	return (s == ustr);
-}
-
-bool test_14() {
-	OS::get_singleton()->print("\n\nTest 14: ASCII\n");
-
-	String s = L"Primero Leche";
-	OS::get_singleton()->print("\tAscii: %s\n", s.ascii().get_data());
-
-	String t = s.ascii().get_data();
-	return (s == t);
-}
-
-bool test_15() {
-	OS::get_singleton()->print("\n\nTest 15: substr\n");
-
-	String s = "Killer Baby";
-	OS::get_singleton()->print("\tsubstr(3,4) of \"%ls\" is \"%ls\"\n", s.c_str(), s.substr(3, 4).c_str());
-
-	return (s.substr(3, 4) == "ler ");
-}
-
-bool test_16() {
-	OS::get_singleton()->print("\n\nTest 16: find\n");
-
-	String s = "Pretty Woman";
-	OS::get_singleton()->print("\tString: %ls\n", s.c_str());
-	OS::get_singleton()->print("\t\"tty\" is at %i pos.\n", s.find("tty"));
-	OS::get_singleton()->print("\t\"Revenge of the Monster Truck\" is at %i pos.\n", s.find("Revenge of the Monster Truck"));
-
-	if (s.find("tty") != 3) {
-		return false;
-	}
-
-	if (s.find("Revenge of the Monster Truck") != -1) {
-		return false;
-	}
-
-	return true;
-}
-
-bool test_17() {
-	OS::get_singleton()->print("\n\nTest 17: find no case\n");
-
-	String s = "Pretty Whale";
-	OS::get_singleton()->print("\tString: %ls\n", s.c_str());
-	OS::get_singleton()->print("\t\"WHA\" is at %i pos.\n", s.findn("WHA"));
-	OS::get_singleton()->print("\t\"Revenge of the Monster SawFish\" is at %i pos.\n", s.findn("Revenge of the Monster Truck"));
-
-	if (s.findn("WHA") != 7) {
-		return false;
-	}
-
-	if (s.findn("Revenge of the Monster SawFish") != -1) {
-		return false;
-	}
-
-	return true;
-}
-
-bool test_18() {
-	OS::get_singleton()->print("\n\nTest 18: find no case\n");
-
-	String s = "Pretty Whale";
-	OS::get_singleton()->print("\tString: %ls\n", s.c_str());
-	OS::get_singleton()->print("\t\"WHA\" is at %i pos.\n", s.findn("WHA"));
-	OS::get_singleton()->print("\t\"Revenge of the Monster SawFish\" is at %i pos.\n", s.findn("Revenge of the Monster Truck"));
-
-	if (s.findn("WHA") != 7) {
-		return false;
-	}
-
-	if (s.findn("Revenge of the Monster SawFish") != -1) {
-		return false;
-	}
-
-	return true;
-}
-
-bool test_19() {
-	OS::get_singleton()->print("\n\nTest 19: Search & replace\n");
-
-	String s = "Happy Birthday, Anna!";
-	OS::get_singleton()->print("\tString: %ls\n", s.c_str());
-
-	s = s.replace("Birthday", "Halloween");
-	OS::get_singleton()->print("\tReplaced Birthday/Halloween: %ls.\n", s.c_str());
-
-	return (s == "Happy Halloween, Anna!");
-}
-
-bool test_20() {
-	OS::get_singleton()->print("\n\nTest 20: Insertion\n");
-
-	String s = "Who is Frederic?";
-
-	OS::get_singleton()->print("\tString: %ls\n", s.c_str());
-	s = s.insert(s.find("?"), " Chopin");
-	OS::get_singleton()->print("\tInserted Chopin: %ls.\n", s.c_str());
-
-	return (s == "Who is Frederic Chopin?");
-}
-
-bool test_21() {
-	OS::get_singleton()->print("\n\nTest 21: Number -> String\n");
-
-	OS::get_singleton()->print("\tPi is %f\n", 33.141593);
-	OS::get_singleton()->print("\tPi String is %ls\n", String::num(3.141593).c_str());
-
-	return String::num(3.141593) == "3.141593";
-}
-
-bool test_22() {
-	OS::get_singleton()->print("\n\nTest 22: String -> Int\n");
-
-	static const char *nums[4] = { "1237461283", "- 22", "0", " - 1123412" };
-	static const int num[4] = { 1237461283, -22, 0, -1123412 };
-
-	for (int i = 0; i < 4; i++) {
-#ifdef __MINGW32__ // MinGW can't handle normal format specifiers for some reason. So we need special code just for MinGW.
-		OS::get_singleton()->print("\tString: \"%s\" as Int is %I64i\n", nums[i], (long long)(String(nums[i]).to_int()));
-#else
-		OS::get_singleton()->print("\tString: \"%s\" as Int is %lli\n", nums[i], (long long)(String(nums[i]).to_int()));
-#endif
-		if (String(nums[i]).to_int() != num[i]) {
-			return false;
-		}
-	}
-
-	return true;
-}
-
-bool test_23() {
-	OS::get_singleton()->print("\n\nTest 23: String -> Float\n");
-
-	static const char *nums[4] = { "-12348298412.2", "0.05", "2.0002", " -0.0001" };
-	static const double num[4] = { -12348298412.2, 0.05, 2.0002, -0.0001 };
-
-	for (int i = 0; i < 4; i++) {
-		OS::get_singleton()->print("\tString: \"%s\" as Float is %f\n", nums[i], String(nums[i]).to_double());
-
-		if (ABS(String(nums[i]).to_double() - num[i]) > 0.00001) {
-			return false;
-		}
-	}
-
-	return true;
-}
-
-bool test_24() {
-	OS::get_singleton()->print("\n\nTest 24: Slicing\n");
-
-	String s = "Mars,Jupiter,Saturn,Uranus";
-
-	const char *slices[4] = { "Mars", "Jupiter", "Saturn", "Uranus" };
-
-	OS::get_singleton()->print("\tSlicing \"%ls\" by \"%s\"..\n", s.c_str(), ",");
-
-	for (int i = 0; i < s.get_slice_count(","); i++) {
-		OS::get_singleton()->print("\t\t%i- %ls\n", i + 1, s.get_slice(",", i).c_str());
-
-		if (s.get_slice(",", i) != slices[i]) {
-			return false;
-		}
-	}
-
-	return true;
-}
-
-bool test_25() {
-	OS::get_singleton()->print("\n\nTest 25: Erasing\n");
-
-	String s = "Josephine is such a cute girl!";
-
-	OS::get_singleton()->print("\tString: %ls\n", s.c_str());
-	OS::get_singleton()->print("\tRemoving \"cute\"\n");
-
-	s.erase(s.find("cute "), String("cute ").length());
-	OS::get_singleton()->print("\tResult: %ls\n", s.c_str());
-
-	return (s == "Josephine is such a girl!");
-}
-
-bool test_26() {
-	OS::get_singleton()->print("\n\nTest 26: RegEx substitution\n");
-
-#ifndef MODULE_REGEX_ENABLED
-	OS::get_singleton()->print("\tRegEx module disabled, can't run test.");
-	return false;
-#else
-	String s = "Double all the vowels.";
-
-	OS::get_singleton()->print("\tString: %ls\n", s.c_str());
-	OS::get_singleton()->print("\tRepeating instances of 'aeiou' once\n");
-
-	RegEx re("(?<vowel>[aeiou])");
-	s = re.sub(s, "$0$vowel", true);
-
-	OS::get_singleton()->print("\tResult: %ls\n", s.c_str());
-
-	return (s == "Doouublee aall thee vooweels.");
-#endif
-}
-
-struct test_27_data {
-	char const *data;
-	char const *begin;
-	bool expected;
-};
-
-bool test_27() {
-	OS::get_singleton()->print("\n\nTest 27: begins_with\n");
-	test_27_data tc[] = {
-		{ "res://foobar", "res://", true },
-		{ "res", "res://", false },
-		{ "abc", "abc", true }
-	};
-	size_t count = sizeof(tc) / sizeof(tc[0]);
-	bool state = true;
-	for (size_t i = 0; state && i < count; ++i) {
-		String s = tc[i].data;
-		state = s.begins_with(tc[i].begin) == tc[i].expected;
-		if (state) {
-			String sb = tc[i].begin;
-			state = s.begins_with(sb) == tc[i].expected;
-		}
-		if (!state) {
-			OS::get_singleton()->print("\n\t Failure on:\n\t\tstring: %s\n\t\tbegin: %s\n\t\texpected: %s\n", tc[i].data, tc[i].begin, tc[i].expected ? "true" : "false");
-			break;
-		}
-	};
-	return state;
-};
-
-bool test_28() {
-	OS::get_singleton()->print("\n\nTest 28: sprintf\n");
-
-	bool success, state = true;
-	char output_format[] = "\tTest:\t%ls => %ls (%s)\n";
-	String format, output;
-	Array args;
-	bool error;
-
-	// %%
-	format = "fish %% frog";
-	args.clear();
-	output = format.sprintf(args, &error);
-	success = (output == String("fish % frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	//////// INTS
-
-	// Int
-	format = "fish %d frog";
-	args.clear();
-	args.push_back(5);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish 5 frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Int left padded with zeroes.
-	format = "fish %05d frog";
-	args.clear();
-	args.push_back(5);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish 00005 frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Int left padded with spaces.
-	format = "fish %5d frog";
-	args.clear();
-	args.push_back(5);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish     5 frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Int right padded with spaces.
-	format = "fish %-5d frog";
-	args.clear();
-	args.push_back(5);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish 5     frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Int with sign (positive).
-	format = "fish %+d frog";
-	args.clear();
-	args.push_back(5);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish +5 frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Negative int.
-	format = "fish %d frog";
-	args.clear();
-	args.push_back(-5);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish -5 frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Hex (lower)
-	format = "fish %x frog";
-	args.clear();
-	args.push_back(45);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish 2d frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Hex (upper)
-	format = "fish %X frog";
-	args.clear();
-	args.push_back(45);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish 2D frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Octal
-	format = "fish %o frog";
-	args.clear();
-	args.push_back(99);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish 143 frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	////// REALS
-
-	// Real
-	format = "fish %f frog";
-	args.clear();
-	args.push_back(99.99);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish 99.990000 frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Real left-padded
-	format = "fish %11f frog";
-	args.clear();
-	args.push_back(99.99);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish   99.990000 frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Real right-padded
-	format = "fish %-11f frog";
-	args.clear();
-	args.push_back(99.99);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish 99.990000   frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Real given int.
-	format = "fish %f frog";
-	args.clear();
-	args.push_back(99);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish 99.000000 frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Real with sign (positive).
-	format = "fish %+f frog";
-	args.clear();
-	args.push_back(99.99);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish +99.990000 frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Real with 1 decimals.
-	format = "fish %.1f frog";
-	args.clear();
-	args.push_back(99.99);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish 100.0 frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Real with 12 decimals.
-	format = "fish %.12f frog";
-	args.clear();
-	args.push_back(99.99);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish 99.990000000000 frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Real with no decimals.
-	format = "fish %.f frog";
-	args.clear();
-	args.push_back(99.99);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish 100 frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	/////// Strings.
-
-	// String
-	format = "fish %s frog";
-	args.clear();
-	args.push_back("cheese");
-	output = format.sprintf(args, &error);
-	success = (output == String("fish cheese frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// String left-padded
-	format = "fish %10s frog";
-	args.clear();
-	args.push_back("cheese");
-	output = format.sprintf(args, &error);
-	success = (output == String("fish     cheese frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// String right-padded
-	format = "fish %-10s frog";
-	args.clear();
-	args.push_back("cheese");
-	output = format.sprintf(args, &error);
-	success = (output == String("fish cheese     frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	///// Characters
-
-	// Character as string.
-	format = "fish %c frog";
-	args.clear();
-	args.push_back("A");
-	output = format.sprintf(args, &error);
-	success = (output == String("fish A frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Character as int.
-	format = "fish %c frog";
-	args.clear();
-	args.push_back(65);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish A frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	///// Dynamic width
-
-	// String dynamic width
-	format = "fish %*s frog";
-	args.clear();
-	args.push_back(10);
-	args.push_back("cheese");
-	output = format.sprintf(args, &error);
-	success = (output == String("fish     cheese frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Int dynamic width
-	format = "fish %*d frog";
-	args.clear();
-	args.push_back(10);
-	args.push_back(99);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish         99 frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Float dynamic width
-	format = "fish %*.*f frog";
-	args.clear();
-	args.push_back(10);
-	args.push_back(3);
-	args.push_back(99.99);
-	output = format.sprintf(args, &error);
-	success = (output == String("fish     99.990 frog") && !error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	///// Errors
-
-	// More formats than arguments.
-	format = "fish %s %s frog";
-	args.clear();
-	args.push_back("cheese");
-	output = format.sprintf(args, &error);
-	success = (output == "not enough arguments for format string" && error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// More arguments than formats.
-	format = "fish %s frog";
-	args.clear();
-	args.push_back("hello");
-	args.push_back("cheese");
-	output = format.sprintf(args, &error);
-	success = (output == "not all arguments converted during string formatting" && error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Incomplete format.
-	format = "fish %10";
-	args.clear();
-	args.push_back("cheese");
-	output = format.sprintf(args, &error);
-	success = (output == "incomplete format" && error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Bad character in format string
-	format = "fish %&f frog";
-	args.clear();
-	args.push_back("cheese");
-	output = format.sprintf(args, &error);
-	success = (output == "unsupported format character" && error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Too many decimals.
-	format = "fish %2.2.2f frog";
-	args.clear();
-	args.push_back(99.99);
-	output = format.sprintf(args, &error);
-	success = (output == "too many decimal points in format" && error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// * not a number
-	format = "fish %*f frog";
-	args.clear();
-	args.push_back("cheese");
-	args.push_back(99.99);
-	output = format.sprintf(args, &error);
-	success = (output == "* wants number" && error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Character too long.
-	format = "fish %c frog";
-	args.clear();
-	args.push_back("sc");
-	output = format.sprintf(args, &error);
-	success = (output == "%c requires number or single-character string" && error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	// Character bad type.
-	format = "fish %c frog";
-	args.clear();
-	args.push_back(Array());
-	output = format.sprintf(args, &error);
-	success = (output == "%c requires number or single-character string" && error);
-	OS::get_singleton()->print(output_format, format.c_str(), output.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	return state;
-}
-
-bool test_29() {
-	bool state = true;
-
-	IP_Address ip0("2001:0db8:85a3:0000:0000:8a2e:0370:7334");
-	OS::get_singleton()->print("ip0 is %ls\n", String(ip0).c_str());
-
-	IP_Address ip(0x0123, 0x4567, 0x89ab, 0xcdef, true);
-	OS::get_singleton()->print("ip6 is %ls\n", String(ip).c_str());
-
-	IP_Address ip2("fe80::52e5:49ff:fe93:1baf");
-	OS::get_singleton()->print("ip6 is %ls\n", String(ip2).c_str());
-
-	IP_Address ip3("::ffff:192.168.0.1");
-	OS::get_singleton()->print("ip6 is %ls\n", String(ip3).c_str());
-
-	String ip4 = "192.168.0.1";
-	bool success = ip4.is_valid_ip_address();
-	OS::get_singleton()->print("Is valid ipv4: %ls, %s\n", ip4.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	ip4 = "192.368.0.1";
-	success = (!ip4.is_valid_ip_address());
-	OS::get_singleton()->print("Is invalid ipv4: %ls, %s\n", ip4.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	String ip6 = "2001:0db8:85a3:0000:0000:8a2e:0370:7334";
-	success = ip6.is_valid_ip_address();
-	OS::get_singleton()->print("Is valid ipv6: %ls, %s\n", ip6.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	ip6 = "2001:0db8:85j3:0000:0000:8a2e:0370:7334";
-	success = (!ip6.is_valid_ip_address());
-	OS::get_singleton()->print("Is invalid ipv6: %ls, %s\n", ip6.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	ip6 = "2001:0db8:85f345:0000:0000:8a2e:0370:7334";
-	success = (!ip6.is_valid_ip_address());
-	OS::get_singleton()->print("Is invalid ipv6: %ls, %s\n", ip6.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	ip6 = "2001:0db8::0:8a2e:370:7334";
-	success = (ip6.is_valid_ip_address());
-	OS::get_singleton()->print("Is valid ipv6: %ls, %s\n", ip6.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	ip6 = "::ffff:192.168.0.1";
-	success = (ip6.is_valid_ip_address());
-	OS::get_singleton()->print("Is valid ipv6: %ls, %s\n", ip6.c_str(), success ? "OK" : "FAIL");
-	state = state && success;
-
-	return state;
-};
-
-bool test_30() {
-	bool state = true;
-	bool success = true;
-	String input = "bytes2var";
-	String output = "Bytes 2 Var";
-	success = (input.capitalize() == output);
-	state = state && success;
-	OS::get_singleton()->print("Capitalize %ls: %ls, %s\n", input.c_str(), output.c_str(), success ? "OK" : "FAIL");
-
-	input = "linear2db";
-	output = "Linear 2 Db";
-	success = (input.capitalize() == output);
-	state = state && success;
-	OS::get_singleton()->print("Capitalize %ls: %ls, %s\n", input.c_str(), output.c_str(), success ? "OK" : "FAIL");
-
-	input = "vector3";
-	output = "Vector 3";
-	success = (input.capitalize() == output);
-	state = state && success;
-	OS::get_singleton()->print("Capitalize %ls: %ls, %s\n", input.c_str(), output.c_str(), success ? "OK" : "FAIL");
-
-	input = "sha256";
-	output = "Sha 256";
-	success = (input.capitalize() == output);
-	state = state && success;
-	OS::get_singleton()->print("Capitalize %ls: %ls, %s\n", input.c_str(), output.c_str(), success ? "OK" : "FAIL");
-
-	input = "2db";
-	output = "2 Db";
-	success = (input.capitalize() == output);
-	state = state && success;
-	OS::get_singleton()->print("Capitalize %ls: %ls, %s\n", input.c_str(), output.c_str(), success ? "OK" : "FAIL");
-
-	input = "PascalCase";
-	output = "Pascal Case";
-	success = (input.capitalize() == output);
-	state = state && success;
-	OS::get_singleton()->print("Capitalize %ls: %ls, %s\n", input.c_str(), output.c_str(), success ? "OK" : "FAIL");
-
-	input = "PascalPascalCase";
-	output = "Pascal Pascal Case";
-	success = (input.capitalize() == output);
-	state = state && success;
-	OS::get_singleton()->print("Capitalize %ls: %ls, %s\n", input.c_str(), output.c_str(), success ? "OK" : "FAIL");
-
-	input = "snake_case";
-	output = "Snake Case";
-	success = (input.capitalize() == output);
-	state = state && success;
-	OS::get_singleton()->print("Capitalize %ls: %ls, %s\n", input.c_str(), output.c_str(), success ? "OK" : "FAIL");
-
-	input = "snake_snake_case";
-	output = "Snake Snake Case";
-	success = (input.capitalize() == output);
-	state = state && success;
-	OS::get_singleton()->print("Capitalize %ls: %ls, %s\n", input.c_str(), output.c_str(), success ? "OK" : "FAIL");
-
-	input = "sha256sum";
-	output = "Sha 256 Sum";
-	success = (input.capitalize() == output);
-	state = state && success;
-	OS::get_singleton()->print("Capitalize %ls: %ls, %s\n", input.c_str(), output.c_str(), success ? "OK" : "FAIL");
-
-	input = "cat2dog";
-	output = "Cat 2 Dog";
-	success = (input.capitalize() == output);
-	state = state && success;
-	OS::get_singleton()->print("Capitalize %ls: %ls, %s\n", input.c_str(), output.c_str(), success ? "OK" : "FAIL");
-
-	input = "function(name)";
-	output = "Function(name)";
-	success = (input.capitalize() == output);
-	state = state && success;
-	OS::get_singleton()->print("Capitalize %ls (existing incorrect behavior): %ls, %s\n", input.c_str(), output.c_str(), success ? "OK" : "FAIL");
-
-	input = "snake_case_function(snake_case_arg)";
-	output = "Snake Case Function(snake Case Arg)";
-	success = (input.capitalize() == output);
-	state = state && success;
-	OS::get_singleton()->print("Capitalize %ls (existing incorrect behavior): %ls, %s\n", input.c_str(), output.c_str(), success ? "OK" : "FAIL");
-
-	input = "snake_case_function( snake_case_arg )";
-	output = "Snake Case Function( Snake Case Arg )";
-	success = (input.capitalize() == output);
-	state = state && success;
-	OS::get_singleton()->print("Capitalize %ls: %ls, %s\n", input.c_str(), output.c_str(), success ? "OK" : "FAIL");
-
-	return state;
-}
-
-bool test_31() {
-	bool state = true;
-	bool success;
-
-	String a = "";
-	success = a[0] == 0;
-	OS::get_singleton()->print("Is 0 String[0]:, %s\n", success ? "OK" : "FAIL");
-	if (!success) {
-		state = false;
-	}
-
-	String b = "Godot";
-	success = b[b.size()] == 0;
-	OS::get_singleton()->print("Is 0 String[size()]:, %s\n", success ? "OK" : "FAIL");
-	if (!success) {
-		state = false;
-	}
-
-	const String c = "";
-	success = c[0] == 0;
-	OS::get_singleton()->print("Is 0 const String[0]:, %s\n", success ? "OK" : "FAIL");
-	if (!success) {
-		state = false;
-	}
-
-	const String d = "Godot";
-	success = d[d.size()] == 0;
-	OS::get_singleton()->print("Is 0 const String[size()]:, %s\n", success ? "OK" : "FAIL");
-	if (!success) {
-		state = false;
-	}
-
-	return state;
-};
-
-bool test_32() {
-#define STRIP_TEST(x)                                            \
-	{                                                            \
-		bool success = x;                                        \
-		state = state && success;                                \
-		if (!success) {                                          \
-			OS::get_singleton()->print("\tfailed at: %s\n", #x); \
-		}                                                        \
-	}
-
-	OS::get_singleton()->print("\n\nTest 32: lstrip and rstrip\n");
-	bool state = true;
-
-	// strip none
-	STRIP_TEST(String("abc").lstrip("") == "abc");
-	STRIP_TEST(String("abc").rstrip("") == "abc");
-	// strip one
-	STRIP_TEST(String("abc").lstrip("a") == "bc");
-	STRIP_TEST(String("abc").rstrip("c") == "ab");
-	// strip lots
-	STRIP_TEST(String("bababbababccc").lstrip("ab") == "ccc");
-	STRIP_TEST(String("aaabcbcbcbbcbbc").rstrip("cb") == "aaa");
-	// strip empty string
-	STRIP_TEST(String("").lstrip("") == "");
-	STRIP_TEST(String("").rstrip("") == "");
-	// strip to empty string
-	STRIP_TEST(String("abcabcabc").lstrip("bca") == "");
-	STRIP_TEST(String("abcabcabc").rstrip("bca") == "");
-	// don't strip wrong end
-	STRIP_TEST(String("abc").lstrip("c") == "abc");
-	STRIP_TEST(String("abca").lstrip("a") == "bca");
-	STRIP_TEST(String("abc").rstrip("a") == "abc");
-	STRIP_TEST(String("abca").rstrip("a") == "abc");
-	// in utf-8 "¿" (\u00bf) has the same first byte as "µ" (\u00b5)
-	// and the same second as "ÿ" (\u00ff)
-	STRIP_TEST(String::utf8("¿").lstrip(String::utf8("µÿ")) == String::utf8("¿"));
-	STRIP_TEST(String::utf8("¿").rstrip(String::utf8("µÿ")) == String::utf8("¿"));
-	STRIP_TEST(String::utf8("µ¿ÿ").lstrip(String::utf8("µÿ")) == String::utf8("¿ÿ"));
-	STRIP_TEST(String::utf8("µ¿ÿ").rstrip(String::utf8("µÿ")) == String::utf8("µ¿"));
-
-	// the above tests repeated with additional superfluous strip chars
-
-	// strip none
-	STRIP_TEST(String("abc").lstrip("qwjkl") == "abc");
-	STRIP_TEST(String("abc").rstrip("qwjkl") == "abc");
-	// strip one
-	STRIP_TEST(String("abc").lstrip("qwajkl") == "bc");
-	STRIP_TEST(String("abc").rstrip("qwcjkl") == "ab");
-	// strip lots
-	STRIP_TEST(String("bababbababccc").lstrip("qwabjkl") == "ccc");
-	STRIP_TEST(String("aaabcbcbcbbcbbc").rstrip("qwcbjkl") == "aaa");
-	// strip empty string
-	STRIP_TEST(String("").lstrip("qwjkl") == "");
-	STRIP_TEST(String("").rstrip("qwjkl") == "");
-	// strip to empty string
-	STRIP_TEST(String("abcabcabc").lstrip("qwbcajkl") == "");
-	STRIP_TEST(String("abcabcabc").rstrip("qwbcajkl") == "");
-	// don't strip wrong end
-	STRIP_TEST(String("abc").lstrip("qwcjkl") == "abc");
-	STRIP_TEST(String("abca").lstrip("qwajkl") == "bca");
-	STRIP_TEST(String("abc").rstrip("qwajkl") == "abc");
-	STRIP_TEST(String("abca").rstrip("qwajkl") == "abc");
-	// in utf-8 "¿" (\u00bf) has the same first byte as "µ" (\u00b5)
-	// and the same second as "ÿ" (\u00ff)
-	STRIP_TEST(String::utf8("¿").lstrip(String::utf8("qwaµÿjkl")) == String::utf8("¿"));
-	STRIP_TEST(String::utf8("¿").rstrip(String::utf8("qwaµÿjkl")) == String::utf8("¿"));
-	STRIP_TEST(String::utf8("µ¿ÿ").lstrip(String::utf8("qwaµÿjkl")) == String::utf8("¿ÿ"));
-	STRIP_TEST(String::utf8("µ¿ÿ").rstrip(String::utf8("qwaµÿjkl")) == String::utf8("µ¿"));
-
-	return state;
-
-#undef STRIP_TEST
-}
-
-bool test_33() {
-	OS::get_singleton()->print("\n\nTest 33: parse_utf8(null, -1)\n");
-
-	String empty;
-	return empty.parse_utf8(nullptr, -1);
-}
-
-bool test_34() {
-	OS::get_singleton()->print("\n\nTest 34: Cyrillic to_lower()\n");
-
-	String upper = String::utf8("АБВГДЕЁЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯ");
-	String lower = String::utf8("абвгдеёжзийклмнопрстуфхцчшщъыьэюя");
-
-	String test = upper.to_lower();
-
-	bool state = test == lower;
-
-	return state;
-}
-
-bool test_35() {
-#define COUNT_TEST(x)                                            \
-	{                                                            \
-		bool success = x;                                        \
-		state = state && success;                                \
-		if (!success) {                                          \
-			OS::get_singleton()->print("\tfailed at: %s\n", #x); \
-		}                                                        \
-	}
-
-	OS::get_singleton()->print("\n\nTest 35: count and countn function\n");
-	bool state = true;
-
-	COUNT_TEST(String("").count("Test") == 0);
-	COUNT_TEST(String("Test").count("") == 0);
-	COUNT_TEST(String("Test").count("test") == 0);
-	COUNT_TEST(String("Test").count("TEST") == 0);
-	COUNT_TEST(String("TEST").count("TEST") == 1);
-	COUNT_TEST(String("Test").count("Test") == 1);
-	COUNT_TEST(String("aTest").count("Test") == 1);
-	COUNT_TEST(String("Testa").count("Test") == 1);
-	COUNT_TEST(String("TestTestTest").count("Test") == 3);
-	COUNT_TEST(String("TestTestTest").count("TestTest") == 1);
-	COUNT_TEST(String("TestGodotTestGodotTestGodot").count("Test") == 3);
-
-	COUNT_TEST(String("TestTestTestTest").count("Test", 4, 8) == 1);
-	COUNT_TEST(String("TestTestTestTest").count("Test", 4, 12) == 2);
-	COUNT_TEST(String("TestTestTestTest").count("Test", 4, 16) == 3);
-	COUNT_TEST(String("TestTestTestTest").count("Test", 4) == 3);
-
-	COUNT_TEST(String("Test").countn("test") == 1);
-	COUNT_TEST(String("Test").countn("TEST") == 1);
-	COUNT_TEST(String("testTest-Testatest").countn("tEst") == 4);
-	COUNT_TEST(String("testTest-TeStatest").countn("tEsT", 4, 16) == 2);
-
-	return state;
-}
-
-typedef bool (*TestFunc)();
-
-TestFunc test_funcs[] = {
-
-	test_1,
-	test_2,
-	test_3,
-	test_4,
-	test_5,
-	test_6,
-	test_7,
-	test_8,
-	test_9,
-	test_10,
-	test_11,
-	test_12,
-	test_13,
-	test_14,
-	test_15,
-	test_16,
-	test_17,
-	test_18,
-	test_19,
-	test_20,
-	test_21,
-	test_22,
-	test_23,
-	test_24,
-	test_25,
-	test_26,
-	test_27,
-	test_28,
-	test_29,
-	test_30,
-	test_31,
-	test_32,
-	test_33,
-	test_34,
-	test_35,
-	nullptr
-
-};
-
-MainLoop *test() {
-	/** A character length != wchar_t may be forced, so the tests won't work */
-
-	static_assert(sizeof(CharType) == sizeof(wchar_t));
-
-	int count = 0;
-	int passed = 0;
-
-	while (true) {
-		if (!test_funcs[count]) {
-			break;
-		}
-		bool pass = test_funcs[count]();
-		if (pass) {
-			passed++;
-		}
-		OS::get_singleton()->print("\t%s\n", pass ? "PASS" : "FAILED");
-
-		count++;
-	}
-
-	OS::get_singleton()->print("\n\n\n");
-	OS::get_singleton()->print("*************\n");
-	OS::get_singleton()->print("***TOTALS!***\n");
-	OS::get_singleton()->print("*************\n");
-
-	OS::get_singleton()->print("Passed %i of %i tests\n", passed, count);
-
-	return nullptr;
-}
-
-} // namespace TestString
diff --git a/main/tests/test_string.h b/main/tests/test_string.h
index 96fa811126..25fd513a1a 100644
--- a/main/tests/test_string.h
+++ b/main/tests/test_string.h
@@ -31,12 +31,768 @@
 #ifndef TEST_STRING_H
 #define TEST_STRING_H
 
+#include <inttypes.h>
+#include <stdio.h>
+#include <wchar.h>
+
+#include "core/io/ip_address.h"
 #include "core/os/main_loop.h"
+#include "core/os/os.h"
 #include "core/ustring.h"
 
+#ifdef MODULE_REGEX_ENABLED
+#include "modules/regex/regex.h"
+#endif
+
+#include "thirdparty/doctest/doctest.h"
+
 namespace TestString {
 
-MainLoop *test();
+TEST_CASE("[String] Assign from cstr") {
+	String s = "Hello";
+	CHECK(wcscmp(s.c_str(), L"Hello") == 0);
+}
+
+TEST_CASE("[String] Assign from string (operator=)") {
+	String s = "Dolly";
+	const String &t = s;
+	CHECK(wcscmp(t.c_str(), L"Dolly") == 0);
+}
+
+TEST_CASE("[String] Assign from c-string (copycon)") {
+	String s("Sheep");
+	const String &t(s);
+	CHECK(wcscmp(t.c_str(), L"Sheep") == 0);
+}
+
+TEST_CASE("[String] Assign from c-widechar (operator=)") {
+	String s(L"Give me");
+	CHECK(wcscmp(s.c_str(), L"Give me") == 0);
+}
+
+TEST_CASE("[String] Assign from c-widechar (copycon)") {
+	String s(L"Wool");
+	CHECK(wcscmp(s.c_str(), L"Wool") == 0);
+}
+
+TEST_CASE("[String] Comparisons (equal)") {
+	String s = "Test Compare";
+	CHECK(s == "Test Compare");
+	CHECK(s == L"Test Compare");
+	CHECK(s == String("Test Compare"));
+}
+
+TEST_CASE("[String] Comparisons (not equal)") {
+	String s = "Test Compare";
+	CHECK(s != "Peanut");
+	CHECK(s != L"Coconut");
+	CHECK(s != String("Butter"));
+}
+
+TEST_CASE("[String] Comparisons (operator <)") {
+	String s = "Bees";
+	CHECK(s < "Elephant");
+	CHECK(!(s < L"Amber"));
+	CHECK(!(s < String("Beatrix")));
+}
+
+TEST_CASE("[String] Concatenation") {
+	String s;
+
+	s += "Have";
+	s += ' ';
+	s += 'a';
+	s += String(" ");
+	s = s + L"Nice";
+	s = s + " ";
+	s = s + String("Day");
+
+	CHECK(s == "Have a Nice Day");
+}
+
+TEST_CASE("[String] Testing size and length of string") {
+	// todo: expand this test to do more tests on size() as it is complicated under the hood.
+	CHECK(String("Mellon").size() == 7);
+	CHECK(String("Mellon1").size() == 8);
+
+	// length works fine and is easier to test
+	CHECK(String("Mellon").length() == 6);
+	CHECK(String("Mellon1").length() == 7);
+	CHECK(String("Mellon2").length() == 7);
+	CHECK(String("Mellon3").length() == 7);
+}
+
+TEST_CASE("[String] Testing for empty string") {
+	CHECK(!String("Mellon").empty());
+	// do this more than once, to check for string corruption
+	CHECK(String("").empty());
+	CHECK(String("").empty());
+	CHECK(String("").empty());
+}
+
+TEST_CASE("[String] Operator []") {
+	String a = "Kugar Sane";
+	a[0] = 'S';
+	a[6] = 'C';
+	CHECK(a == "Sugar Cane");
+	CHECK(a[1] == 'u');
+}
+
+TEST_CASE("[String] Case function test") {
+	String a = "MoMoNgA";
+
+	CHECK(a.to_upper() == "MOMONGA");
+	CHECK(a.nocasecmp_to("momonga") == 0);
+}
+
+TEST_CASE("[String] UTF8") {
+	/* how can i embed UTF in here? */
+	static const CharType ustr[] = { 0x304A, 0x360F, 0x3088, 0x3046, 0 };
+	//static const wchar_t ustr[] = { 'P', 0xCE, 'p',0xD3, 0 };
+	String s = ustr;
+	s.parse_utf8(s.utf8().get_data());
+	CHECK(s == ustr);
+}
+
+TEST_CASE("[String] ASCII") {
+	String s = L"Primero Leche";
+	String t = s.ascii().get_data();
+	CHECK(s == t);
+}
+
+TEST_CASE("[String] Substr") {
+	String s = "Killer Baby";
+	CHECK(s.substr(3, 4) == "ler ");
+}
+
+TEST_CASE("[string] Find") {
+	String s = "Pretty Woman";
+	s.find("Revenge of the Monster Truck");
+
+	CHECK(s.find("tty") == 3);
+	CHECK(s.find("Revenge of the Monster Truck") == -1);
+}
+
+TEST_CASE("[String] find no case") {
+	String s = "Pretty Whale";
+	CHECK(s.findn("WHA") == 7);
+	CHECK(s.findn("Revenge of the Monster SawFish") == -1);
+}
+
+TEST_CASE("[String] Find and replace") {
+	String s = "Happy Birthday, Anna!";
+	s = s.replace("Birthday", "Halloween");
+	CHECK(s == "Happy Halloween, Anna!");
+}
+
+TEST_CASE("[String] Insertion") {
+	String s = "Who is Frederic?";
+	s = s.insert(s.find("?"), " Chopin");
+	CHECK(s == "Who is Frederic Chopin?");
+}
+
+TEST_CASE("[String] Number to string") {
+	CHECK(String::num(3.141593) == "3.141593");
 }
 
+TEST_CASE("[String] String to integer") {
+	static const char *nums[4] = { "1237461283", "- 22", "0", " - 1123412" };
+	static const int num[4] = { 1237461283, -22, 0, -1123412 };
+
+	for (int i = 0; i < 4; i++) {
+		CHECK(String(nums[i]).to_int() == num[i]);
+	}
+}
+
+TEST_CASE("[String] String to float") {
+	static const char *nums[4] = { "-12348298412.2", "0.05", "2.0002", " -0.0001" };
+	static const double num[4] = { -12348298412.2, 0.05, 2.0002, -0.0001 };
+
+	for (int i = 0; i < 4; i++) {
+		CHECK(!(ABS(String(nums[i]).to_double() - num[i]) > 0.00001));
+	}
+}
+
+TEST_CASE("[String] Slicing") {
+	String s = "Mars,Jupiter,Saturn,Uranus";
+
+	const char *slices[4] = { "Mars", "Jupiter", "Saturn", "Uranus" };
+	for (int i = 0; i < s.get_slice_count(","); i++) {
+		CHECK(s.get_slice(",", i) == slices[i]);
+	}
+}
+
+TEST_CASE("[String] Erasing") {
+	String s = "Josephine is such a cute girl!";
+	s.erase(s.find("cute "), String("cute ").length());
+	CHECK(s == "Josephine is such a girl!");
+}
+
+#ifdef MODULE_REGEX_ENABLED
+TEST_CASE("[String] Regex substitution") {
+	String s = "Double all the vowels.";
+	RegEx re("(?<vowel>[aeiou])");
+	s = re.sub(s, "$0$vowel", true);
+	CHECK(s == "Doouublee aall thee vooweels.");
+}
 #endif
+
+struct test_27_data {
+	char const *data;
+	char const *begin;
+	bool expected;
+};
+
+TEST_CASE("[String] Begins with") {
+	test_27_data tc[] = {
+		{ "res://foobar", "res://", true },
+		{ "res", "res://", false },
+		{ "abc", "abc", true }
+	};
+	size_t count = sizeof(tc) / sizeof(tc[0]);
+	bool state = true;
+	for (size_t i = 0; state && i < count; ++i) {
+		String s = tc[i].data;
+		state = s.begins_with(tc[i].begin) == tc[i].expected;
+		if (state) {
+			String sb = tc[i].begin;
+			state = s.begins_with(sb) == tc[i].expected;
+		}
+		CHECK(state);
+		if (!state) {
+			break;
+		}
+	};
+	CHECK(state);
+}
+
+TEST_CASE("[String] sprintf") {
+	String format, output;
+	Array args;
+	bool error;
+
+	// %%
+	format = "fish %% frog";
+	args.clear();
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish % frog"));
+	//////// INTS
+
+	// Int
+	format = "fish %d frog";
+	args.clear();
+	args.push_back(5);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish 5 frog"));
+
+	// Int left padded with zeroes.
+	format = "fish %05d frog";
+	args.clear();
+	args.push_back(5);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish 00005 frog"));
+
+	// Int left padded with spaces.
+	format = "fish %5d frog";
+	args.clear();
+	args.push_back(5);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish     5 frog"));
+
+	// Int right padded with spaces.
+	format = "fish %-5d frog";
+	args.clear();
+	args.push_back(5);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish 5     frog"));
+
+	// Int with sign (positive).
+	format = "fish %+d frog";
+	args.clear();
+	args.push_back(5);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish +5 frog"));
+
+	// Negative int.
+	format = "fish %d frog";
+	args.clear();
+	args.push_back(-5);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish -5 frog"));
+
+	// Hex (lower)
+	format = "fish %x frog";
+	args.clear();
+	args.push_back(45);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish 2d frog"));
+
+	// Hex (upper)
+	format = "fish %X frog";
+	args.clear();
+	args.push_back(45);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish 2D frog"));
+
+	// Octal
+	format = "fish %o frog";
+	args.clear();
+	args.push_back(99);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish 143 frog"));
+
+	////// REALS
+
+	// Real
+	format = "fish %f frog";
+	args.clear();
+	args.push_back(99.99);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish 99.990000 frog"));
+
+	// Real left-padded
+	format = "fish %11f frog";
+	args.clear();
+	args.push_back(99.99);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish   99.990000 frog"));
+
+	// Real right-padded
+	format = "fish %-11f frog";
+	args.clear();
+	args.push_back(99.99);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish 99.990000   frog"));
+
+	// Real given int.
+	format = "fish %f frog";
+	args.clear();
+	args.push_back(99);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish 99.000000 frog"));
+
+	// Real with sign (positive).
+	format = "fish %+f frog";
+	args.clear();
+	args.push_back(99.99);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish +99.990000 frog"));
+
+	// Real with 1 decimals.
+	format = "fish %.1f frog";
+	args.clear();
+	args.push_back(99.99);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish 100.0 frog"));
+
+	// Real with 12 decimals.
+	format = "fish %.12f frog";
+	args.clear();
+	args.push_back(99.99);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish 99.990000000000 frog"));
+
+	// Real with no decimals.
+	format = "fish %.f frog";
+	args.clear();
+	args.push_back(99.99);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish 100 frog"));
+
+	/////// Strings.
+
+	// String
+	format = "fish %s frog";
+	args.clear();
+	args.push_back("cheese");
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish cheese frog"));
+
+	// String left-padded
+	format = "fish %10s frog";
+	args.clear();
+	args.push_back("cheese");
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish     cheese frog"));
+
+	// String right-padded
+	format = "fish %-10s frog";
+	args.clear();
+	args.push_back("cheese");
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish cheese     frog"));
+
+	///// Characters
+
+	// Character as string.
+	format = "fish %c frog";
+	args.clear();
+	args.push_back("A");
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish A frog"));
+
+	// Character as int.
+	format = "fish %c frog";
+	args.clear();
+	args.push_back(65);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish A frog"));
+
+	///// Dynamic width
+
+	// String dynamic width
+	format = "fish %*s frog";
+	args.clear();
+	args.push_back(10);
+	args.push_back("cheese");
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	REQUIRE(output == String("fish     cheese frog"));
+
+	// Int dynamic width
+	format = "fish %*d frog";
+	args.clear();
+	args.push_back(10);
+	args.push_back(99);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	REQUIRE(output == String("fish         99 frog"));
+
+	// Float dynamic width
+	format = "fish %*.*f frog";
+	args.clear();
+	args.push_back(10);
+	args.push_back(3);
+	args.push_back(99.99);
+	output = format.sprintf(args, &error);
+	REQUIRE(error == false);
+	CHECK(output == String("fish     99.990 frog"));
+
+	///// Errors
+
+	// More formats than arguments.
+	format = "fish %s %s frog";
+	args.clear();
+	args.push_back("cheese");
+	output = format.sprintf(args, &error);
+	REQUIRE(error);
+	CHECK(output == "not enough arguments for format string");
+
+	// More arguments than formats.
+	format = "fish %s frog";
+	args.clear();
+	args.push_back("hello");
+	args.push_back("cheese");
+	output = format.sprintf(args, &error);
+	REQUIRE(error);
+	CHECK(output == "not all arguments converted during string formatting");
+
+	// Incomplete format.
+	format = "fish %10";
+	args.clear();
+	args.push_back("cheese");
+	output = format.sprintf(args, &error);
+	REQUIRE(error);
+	CHECK(output == "incomplete format");
+
+	// Bad character in format string
+	format = "fish %&f frog";
+	args.clear();
+	args.push_back("cheese");
+	output = format.sprintf(args, &error);
+	REQUIRE(error);
+	CHECK(output == "unsupported format character");
+
+	// Too many decimals.
+	format = "fish %2.2.2f frog";
+	args.clear();
+	args.push_back(99.99);
+	output = format.sprintf(args, &error);
+	REQUIRE(error);
+	CHECK(output == "too many decimal points in format");
+
+	// * not a number
+	format = "fish %*f frog";
+	args.clear();
+	args.push_back("cheese");
+	args.push_back(99.99);
+	output = format.sprintf(args, &error);
+	REQUIRE(error);
+	CHECK(output == "* wants number");
+
+	// Character too long.
+	format = "fish %c frog";
+	args.clear();
+	args.push_back("sc");
+	output = format.sprintf(args, &error);
+	REQUIRE(error);
+	CHECK(output == "%c requires number or single-character string");
+
+	// Character bad type.
+	format = "fish %c frog";
+	args.clear();
+	args.push_back(Array());
+	output = format.sprintf(args, &error);
+	REQUIRE(error);
+	CHECK(output == "%c requires number or single-character string");
+}
+
+TEST_CASE("[String] IPVX address to string") {
+	IP_Address ip0("2001:0db8:85a3:0000:0000:8a2e:0370:7334");
+	IP_Address ip(0x0123, 0x4567, 0x89ab, 0xcdef, true);
+	IP_Address ip2("fe80::52e5:49ff:fe93:1baf");
+	IP_Address ip3("::ffff:192.168.0.1");
+	String ip4 = "192.168.0.1";
+	CHECK(ip4.is_valid_ip_address());
+
+	ip4 = "192.368.0.1";
+	CHECK(!ip4.is_valid_ip_address());
+
+	String ip6 = "2001:0db8:85a3:0000:0000:8a2e:0370:7334";
+	CHECK(ip6.is_valid_ip_address());
+
+	ip6 = "2001:0db8:85j3:0000:0000:8a2e:0370:7334";
+	CHECK(!ip6.is_valid_ip_address());
+
+	ip6 = "2001:0db8:85f345:0000:0000:8a2e:0370:7334";
+	CHECK(!ip6.is_valid_ip_address());
+
+	ip6 = "2001:0db8::0:8a2e:370:7334";
+	CHECK(ip6.is_valid_ip_address());
+
+	ip6 = "::ffff:192.168.0.1";
+	CHECK(ip6.is_valid_ip_address());
+}
+
+TEST_CASE("[String] Capitalize against many strings") {
+	String input = "bytes2var";
+	String output = "Bytes 2 Var";
+	CHECK(input.capitalize() == output);
+
+	input = "linear2db";
+	output = "Linear 2 Db";
+	CHECK(input.capitalize() == output);
+
+	input = "vector3";
+	output = "Vector 3";
+	CHECK(input.capitalize() == output);
+
+	input = "sha256";
+	output = "Sha 256";
+	CHECK(input.capitalize() == output);
+
+	input = "2db";
+	output = "2 Db";
+	CHECK(input.capitalize() == output);
+
+	input = "PascalCase";
+	output = "Pascal Case";
+	CHECK(input.capitalize() == output);
+
+	input = "PascalPascalCase";
+	output = "Pascal Pascal Case";
+	CHECK(input.capitalize() == output);
+
+	input = "snake_case";
+	output = "Snake Case";
+	CHECK(input.capitalize() == output);
+
+	input = "snake_snake_case";
+	output = "Snake Snake Case";
+	CHECK(input.capitalize() == output);
+
+	input = "sha256sum";
+	output = "Sha 256 Sum";
+	CHECK(input.capitalize() == output);
+
+	input = "cat2dog";
+	output = "Cat 2 Dog";
+	CHECK(input.capitalize() == output);
+
+	input = "function(name)";
+	output = "Function(name)";
+	CHECK(input.capitalize() == output);
+
+	input = "snake_case_function(snake_case_arg)";
+	output = "Snake Case Function(snake Case Arg)";
+	CHECK(input.capitalize() == output);
+
+	input = "snake_case_function( snake_case_arg )";
+	output = "Snake Case Function( Snake Case Arg )";
+	CHECK(input.capitalize() == output);
+}
+
+TEST_CASE("[String] Checking string is empty when it should be") {
+	bool state = true;
+	bool success;
+
+	String a = "";
+	success = a[0] == 0;
+	if (!success) {
+		state = false;
+	}
+	String b = "Godot";
+	success = b[b.size()] == 0;
+	if (!success) {
+		state = false;
+	}
+	const String c = "";
+	success = c[0] == 0;
+	if (!success) {
+		state = false;
+	}
+
+	const String d = "Godot";
+	success = d[d.size()] == 0;
+	if (!success) {
+		state = false;
+	}
+
+	CHECK(state);
+}
+
+TEST_CASE("[String] lstrip and rstrip") {
+#define STRIP_TEST(x)             \
+	{                             \
+		bool success = x;         \
+		state = state && success; \
+	}
+
+	bool state = true;
+
+	// strip none
+	STRIP_TEST(String("abc").lstrip("") == "abc");
+	STRIP_TEST(String("abc").rstrip("") == "abc");
+	// strip one
+	STRIP_TEST(String("abc").lstrip("a") == "bc");
+	STRIP_TEST(String("abc").rstrip("c") == "ab");
+	// strip lots
+	STRIP_TEST(String("bababbababccc").lstrip("ab") == "ccc");
+	STRIP_TEST(String("aaabcbcbcbbcbbc").rstrip("cb") == "aaa");
+	// strip empty string
+	STRIP_TEST(String("").lstrip("") == "");
+	STRIP_TEST(String("").rstrip("") == "");
+	// strip to empty string
+	STRIP_TEST(String("abcabcabc").lstrip("bca") == "");
+	STRIP_TEST(String("abcabcabc").rstrip("bca") == "");
+	// don't strip wrong end
+	STRIP_TEST(String("abc").lstrip("c") == "abc");
+	STRIP_TEST(String("abca").lstrip("a") == "bca");
+	STRIP_TEST(String("abc").rstrip("a") == "abc");
+	STRIP_TEST(String("abca").rstrip("a") == "abc");
+	// in utf-8 "¿" (\u00bf) has the same first byte as "µ" (\u00b5)
+	// and the same second as "ÿ" (\u00ff)
+	STRIP_TEST(String::utf8("¿").lstrip(String::utf8("µÿ")) == String::utf8("¿"));
+	STRIP_TEST(String::utf8("¿").rstrip(String::utf8("µÿ")) == String::utf8("¿"));
+	STRIP_TEST(String::utf8("µ¿ÿ").lstrip(String::utf8("µÿ")) == String::utf8("¿ÿ"));
+	STRIP_TEST(String::utf8("µ¿ÿ").rstrip(String::utf8("µÿ")) == String::utf8("µ¿"));
+
+	// the above tests repeated with additional superfluous strip chars
+
+	// strip none
+	STRIP_TEST(String("abc").lstrip("qwjkl") == "abc");
+	STRIP_TEST(String("abc").rstrip("qwjkl") == "abc");
+	// strip one
+	STRIP_TEST(String("abc").lstrip("qwajkl") == "bc");
+	STRIP_TEST(String("abc").rstrip("qwcjkl") == "ab");
+	// strip lots
+	STRIP_TEST(String("bababbababccc").lstrip("qwabjkl") == "ccc");
+	STRIP_TEST(String("aaabcbcbcbbcbbc").rstrip("qwcbjkl") == "aaa");
+	// strip empty string
+	STRIP_TEST(String("").lstrip("qwjkl") == "");
+	STRIP_TEST(String("").rstrip("qwjkl") == "");
+	// strip to empty string
+	STRIP_TEST(String("abcabcabc").lstrip("qwbcajkl") == "");
+	STRIP_TEST(String("abcabcabc").rstrip("qwbcajkl") == "");
+	// don't strip wrong end
+	STRIP_TEST(String("abc").lstrip("qwcjkl") == "abc");
+	STRIP_TEST(String("abca").lstrip("qwajkl") == "bca");
+	STRIP_TEST(String("abc").rstrip("qwajkl") == "abc");
+	STRIP_TEST(String("abca").rstrip("qwajkl") == "abc");
+	// in utf-8 "¿" (\u00bf) has the same first byte as "µ" (\u00b5)
+	// and the same second as "ÿ" (\u00ff)
+	STRIP_TEST(String::utf8("¿").lstrip(String::utf8("qwaµÿjkl")) == String::utf8("¿"));
+	STRIP_TEST(String::utf8("¿").rstrip(String::utf8("qwaµÿjkl")) == String::utf8("¿"));
+	STRIP_TEST(String::utf8("µ¿ÿ").lstrip(String::utf8("qwaµÿjkl")) == String::utf8("¿ÿ"));
+	STRIP_TEST(String::utf8("µ¿ÿ").rstrip(String::utf8("qwaµÿjkl")) == String::utf8("µ¿"));
+
+	CHECK(state);
+
+#undef STRIP_TEST
+}
+
+TEST_CASE("[String] ensuring empty string into parse_utf8 passes empty string") {
+	String empty;
+	CHECK(empty.parse_utf8(NULL, -1));
+}
+
+TEST_CASE("[String] Cyrillic to_lower()") {
+	String upper = String::utf8("АБВГДЕЁЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯ");
+	String lower = String::utf8("абвгдеёжзийклмнопрстуфхцчшщъыьэюя");
+
+	String test = upper.to_lower();
+
+	bool state = test == lower;
+
+	CHECK(state);
+}
+
+TEST_CASE("[String] Count and countn functionality") {
+#define COUNT_TEST(x)             \
+	{                             \
+		bool success = x;         \
+		state = state && success; \
+	}
+
+	bool state = true;
+
+	COUNT_TEST(String("").count("Test") == 0);
+	COUNT_TEST(String("Test").count("") == 0);
+	COUNT_TEST(String("Test").count("test") == 0);
+	COUNT_TEST(String("Test").count("TEST") == 0);
+	COUNT_TEST(String("TEST").count("TEST") == 1);
+	COUNT_TEST(String("Test").count("Test") == 1);
+	COUNT_TEST(String("aTest").count("Test") == 1);
+	COUNT_TEST(String("Testa").count("Test") == 1);
+	COUNT_TEST(String("TestTestTest").count("Test") == 3);
+	COUNT_TEST(String("TestTestTest").count("TestTest") == 1);
+	COUNT_TEST(String("TestGodotTestGodotTestGodot").count("Test") == 3);
+
+	COUNT_TEST(String("TestTestTestTest").count("Test", 4, 8) == 1);
+	COUNT_TEST(String("TestTestTestTest").count("Test", 4, 12) == 2);
+	COUNT_TEST(String("TestTestTestTest").count("Test", 4, 16) == 3);
+	COUNT_TEST(String("TestTestTestTest").count("Test", 4) == 3);
+
+	COUNT_TEST(String("Test").countn("test") == 1);
+	COUNT_TEST(String("Test").countn("TEST") == 1);
+	COUNT_TEST(String("testTest-Testatest").countn("tEst") == 4);
+	COUNT_TEST(String("testTest-TeStatest").countn("tEsT", 4, 16) == 2);
+
+	CHECK(state);
+}
+} // namespace TestString
+
+#endif // TEST_STRING_H
diff --git a/main/tests/test_validate_testing.h b/main/tests/test_validate_testing.h
new file mode 100644
index 0000000000..5be7d45185
--- /dev/null
+++ b/main/tests/test_validate_testing.h
@@ -0,0 +1,42 @@
+/*************************************************************************/
+/*  test_validate_testing.h                                              */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef TEST_VALIDATE_TESTING_H
+#define TEST_VALIDATE_TESTING_H
+
+#include "core/os/os.h"
+
+#include "thirdparty/doctest/doctest.h"
+
+TEST_CASE("Validate Test will always pass") {
+	CHECK(true);
+}
+
+#endif // TEST_VALIDATE_TESTING_H