SCons: Improve logic to generate `modules_tests.gen.h`

This removes the need for `AlwaysBuild` by ensuring that the proper
files are being tracked as `Depends`.

1 files changed, 27 insertions, 18 deletions

diff --git a/modules/SCsub b/modules/SCsub
index 5ff4623743..fcc01e2c1b 100644
--- a/modules/SCsub
+++ b/modules/SCsub
@@ -22,36 +22,45 @@ env.CommandNoCache(
     ),
 )
 
-# Header to be included in `tests/test_main.cpp` to run module-specific tests.
-if env["tests"]:
-    env.Depends("modules_tests.gen.h", Value(env.module_list))
-    env.CommandNoCache(
-        "modules_tests.gen.h",
-        Value(env.module_list),
-        env.Run(
-            modules_builders.generate_modules_tests,
-            "Generating modules tests header.",
-            # NOTE: No need to run in subprocess since this is still executed serially.
-            subprocess=False,
-        ),
-    )
-    env.AlwaysBuild("modules_tests.gen.h")
 
 vs_sources = []
+test_headers = []
 # libmodule_<name>.a for each active module.
 for name, path in env.module_list.items():
     env.modules_sources = []
 
-    if not os.path.isabs(path):
-        SConscript(name + "/SCsub")  # Built-in.
-    else:
-        SConscript(path + "/SCsub")  # Custom.
+    # Name for built-in modules, (absolute) path for custom ones.
+    base_path = path if os.path.isabs(path) else name
+    SConscript(base_path + "/SCsub")
 
     lib = env_modules.add_library("module_%s" % name, env.modules_sources)
     env.Prepend(LIBS=[lib])
     if env["vsproj"]:
         vs_sources += env.modules_sources
 
+    if env["tests"]:
+        # Lookup potential headers in `tests` subfolder.
+        import glob
+
+        module_tests = sorted(glob.glob(os.path.join(base_path, "tests", "*.h")))
+        if module_tests != []:
+            test_headers += module_tests
+
+
+# Generate header to be included in `tests/test_main.cpp` to run module-specific tests.
+if env["tests"]:
+    env.Depends("modules_tests.gen.h", test_headers)
+    env.CommandNoCache(
+        "modules_tests.gen.h",
+        test_headers,
+        env.Run(
+            modules_builders.generate_modules_tests,
+            "Generating modules tests header.",
+            # NOTE: No need to run in subprocess since this is still executed serially.
+            subprocess=False,
+        ),
+    )
+
 # libmodules.a with only register_module_types.
 # Must be last so that all libmodule_<name>.a libraries are on the right side
 # in the linker command.