Core: Move Rect2i to its own `rect2i.h` header

And take the opportunity to improve interdependencies a bit with forward
declares where possible.

3 files changed, 313 insertions, 277 deletions

diff --git a/tests/core/math/test_rect2.h b/tests/core/math/test_rect2.h
index d98a94b1b5..0b1106ac3c 100644
--- a/tests/core/math/test_rect2.h
+++ b/tests/core/math/test_rect2.h
@@ -32,15 +32,11 @@
 #define TEST_RECT2_H
 
 #include "core/math/rect2.h"
+#include "core/math/rect2i.h"
 
 #include "thirdparty/doctest/doctest.h"
 
 namespace TestRect2 {
-// We also test Rect2i here, for consistency with the source code where Rect2
-// and Rect2i are defined in the same file.
-
-// Rect2
-
 TEST_CASE("[Rect2] Constructor methods") {
 	const Rect2 rect = Rect2(0, 100, 1280, 720);
 	const Rect2 rect_vector = Rect2(Vector2(0, 100), Vector2(1280, 720));
@@ -304,278 +300,6 @@ TEST_CASE("[Rect2] Merging") {
 			Rect2(0, 100, 1280, 720).merge(Rect2(-4000, -4000, 100, 100)).is_equal_approx(Rect2(-4000, -4000, 5280, 4820)),
 			"merge() with non-enclosed Rect2 should return the expected result.");
 }
-
-// Rect2i
-
-TEST_CASE("[Rect2i] Constructor methods") {
-	Rect2i recti = Rect2i(0, 100, 1280, 720);
-	Rect2i recti_vector = Rect2i(Vector2i(0, 100), Vector2i(1280, 720));
-	Rect2i recti_copy_recti = Rect2i(recti);
-	Rect2i recti_copy_rect = Rect2i(Rect2(0, 100, 1280, 720));
-
-	CHECK_MESSAGE(
-			recti == recti_vector,
-			"Rect2is created with the same dimensions but by different methods should be equal.");
-	CHECK_MESSAGE(
-			recti == recti_copy_recti,
-			"Rect2is created with the same dimensions but by different methods should be equal.");
-	CHECK_MESSAGE(
-			recti == recti_copy_rect,
-			"Rect2is created with the same dimensions but by different methods should be equal.");
-}
-
-TEST_CASE("[Rect2i] String conversion") {
-	// Note: This also depends on the Vector2 string representation.
-	CHECK_MESSAGE(
-			String(Rect2i(0, 100, 1280, 720)) == "[P: (0, 100), S: (1280, 720)]",
-			"The string representation should match the expected value.");
-}
-
-TEST_CASE("[Rect2i] Basic getters") {
-	const Rect2i rect = Rect2i(0, 100, 1280, 720);
-	CHECK_MESSAGE(
-			rect.get_position() == Vector2i(0, 100),
-			"get_position() should return the expected value.");
-	CHECK_MESSAGE(
-			rect.get_size() == Vector2i(1280, 720),
-			"get_size() should return the expected value.");
-	CHECK_MESSAGE(
-			rect.get_end() == Vector2i(1280, 820),
-			"get_end() should return the expected value.");
-	CHECK_MESSAGE(
-			rect.get_center() == Vector2i(640, 460),
-			"get_center() should return the expected value.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1281, 721).get_center() == Vector2i(640, 460),
-			"get_center() should return the expected value.");
-}
-
-TEST_CASE("[Rect2i] Basic setters") {
-	Rect2i rect = Rect2i(0, 100, 1280, 720);
-	rect.set_end(Vector2i(4000, 4000));
-	CHECK_MESSAGE(
-			rect == Rect2i(0, 100, 4000, 3900),
-			"set_end() should result in the expected Rect2i.");
-
-	rect = Rect2i(0, 100, 1280, 720);
-	rect.set_position(Vector2i(4000, 4000));
-	CHECK_MESSAGE(
-			rect == Rect2i(4000, 4000, 1280, 720),
-			"set_position() should result in the expected Rect2i.");
-
-	rect = Rect2i(0, 100, 1280, 720);
-	rect.set_size(Vector2i(4000, 4000));
-	CHECK_MESSAGE(
-			rect == Rect2i(0, 100, 4000, 4000),
-			"set_size() should result in the expected Rect2i.");
-}
-
-TEST_CASE("[Rect2i] Area getters") {
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).get_area() == 921'600,
-			"get_area() should return the expected value.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, -1280, -720).get_area() == 921'600,
-			"get_area() should return the expected value.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, -720).get_area() == -921'600,
-			"get_area() should return the expected value.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, -1280, 720).get_area() == -921'600,
-			"get_area() should return the expected value.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 0, 720).get_area() == 0,
-			"get_area() should return the expected value.");
-
-	CHECK_MESSAGE(
-			!Rect2i(0, 100, 1280, 720).has_no_area(),
-			"has_no_area() should return the expected value on Rect2i with an area.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 0, 500).has_no_area(),
-			"has_no_area() should return the expected value on Rect2i with no area.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 500, 0).has_no_area(),
-			"has_no_area() should return the expected value on Rect2i with no area.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 0, 0).has_no_area(),
-			"has_no_area() should return the expected value on Rect2i with no area.");
-}
-
-TEST_CASE("[Rect2i] Absolute coordinates") {
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).abs() == Rect2i(0, 100, 1280, 720),
-			"abs() should return the expected Rect2i.");
-	CHECK_MESSAGE(
-			Rect2i(0, -100, 1280, 720).abs() == Rect2i(0, -100, 1280, 720),
-			"abs() should return the expected Rect2i.");
-	CHECK_MESSAGE(
-			Rect2i(0, -100, -1280, -720).abs() == Rect2i(-1280, -820, 1280, 720),
-			"abs() should return the expected Rect2i.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, -1280, 720).abs() == Rect2i(-1280, 100, 1280, 720),
-			"abs() should return the expected Rect2i.");
-}
-
-TEST_CASE("[Rect2i] Intersection") {
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).intersection(Rect2i(0, 300, 100, 100)) == Rect2i(0, 300, 100, 100),
-			"intersection() with fully enclosed Rect2i should return the expected result.");
-	// The resulting Rect2i is 100 pixels high because the first Rect2i is vertically offset by 100 pixels.
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).intersection(Rect2i(1200, 700, 100, 100)) == Rect2i(1200, 700, 80, 100),
-			"intersection() with partially enclosed Rect2i should return the expected result.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).intersection(Rect2i(-4000, -4000, 100, 100)) == Rect2i(),
-			"intersection() with non-enclosed Rect2i should return the expected result.");
-}
-
-TEST_CASE("[Rect2i] Enclosing") {
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).encloses(Rect2i(0, 300, 100, 100)),
-			"encloses() with fully contained Rect2i should return the expected result.");
-	CHECK_MESSAGE(
-			!Rect2i(0, 100, 1280, 720).encloses(Rect2i(1200, 700, 100, 100)),
-			"encloses() with partially contained Rect2i should return the expected result.");
-	CHECK_MESSAGE(
-			!Rect2i(0, 100, 1280, 720).encloses(Rect2i(-4000, -4000, 100, 100)),
-			"encloses() with non-contained Rect2i should return the expected result.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).encloses(Rect2i(0, 100, 1280, 720)),
-			"encloses() with identical Rect2i should return the expected result.");
-}
-
-TEST_CASE("[Rect2i] Expanding") {
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).expand(Vector2i(500, 600)) == Rect2i(0, 100, 1280, 720),
-			"expand() with contained Vector2i should return the expected result.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).expand(Vector2i(0, 0)) == Rect2i(0, 0, 1280, 820),
-			"expand() with non-contained Vector2i should return the expected result.");
-}
-
-TEST_CASE("[Rect2i] Growing") {
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).grow(100) == Rect2i(-100, 0, 1480, 920),
-			"grow() with positive value should return the expected Rect2i.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).grow(-100) == Rect2i(100, 200, 1080, 520),
-			"grow() with negative value should return the expected Rect2i.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).grow(-4000) == Rect2i(4000, 4100, -6720, -7280),
-			"grow() with large negative value should return the expected Rect2i.");
-
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).grow_individual(100, 200, 300, 400) == Rect2i(-100, -100, 1680, 1320),
-			"grow_individual() with positive values should return the expected Rect2i.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).grow_individual(-100, 200, 300, -400) == Rect2i(100, -100, 1480, 520),
-			"grow_individual() with positive and negative values should return the expected Rect2i.");
-
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).grow_side(SIDE_TOP, 500) == Rect2i(0, -400, 1280, 1220),
-			"grow_side() with positive value should return the expected Rect2i.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).grow_side(SIDE_TOP, -500) == Rect2i(0, 600, 1280, 220),
-			"grow_side() with negative value should return the expected Rect2i.");
-}
-
-TEST_CASE("[Rect2i] Has point") {
-	Rect2i rect = Rect2i(0, 100, 1280, 720);
-	CHECK_MESSAGE(
-			rect.has_point(Vector2i(500, 600)),
-			"has_point() with contained Vector2i should return the expected result.");
-	CHECK_MESSAGE(
-			!rect.has_point(Vector2i(0, 0)),
-			"has_point() with non-contained Vector2i should return the expected result.");
-
-	CHECK_MESSAGE(
-			rect.has_point(rect.position),
-			"has_point() with positive size should include `position`.");
-	CHECK_MESSAGE(
-			rect.has_point(rect.position + Vector2i(1, 1)),
-			"has_point() with positive size should include `position + (1, 1)`.");
-	CHECK_MESSAGE(
-			!rect.has_point(rect.position + Vector2i(1, -1)),
-			"has_point() with positive size should not include `position + (1, -1)`.");
-	CHECK_MESSAGE(
-			!rect.has_point(rect.position + rect.size),
-			"has_point() with positive size should not include `position + size`.");
-	CHECK_MESSAGE(
-			!rect.has_point(rect.position + rect.size + Vector2i(1, 1)),
-			"has_point() with positive size should not include `position + size + (1, 1)`.");
-	CHECK_MESSAGE(
-			rect.has_point(rect.position + rect.size + Vector2i(-1, -1)),
-			"has_point() with positive size should include `position + size + (-1, -1)`.");
-	CHECK_MESSAGE(
-			!rect.has_point(rect.position + rect.size + Vector2i(-1, 1)),
-			"has_point() with positive size should not include `position + size + (-1, 1)`.");
-
-	CHECK_MESSAGE(
-			rect.has_point(rect.position + Vector2i(0, 10)),
-			"has_point() with point located on left edge should return true.");
-	CHECK_MESSAGE(
-			!rect.has_point(rect.position + Vector2i(rect.size.x, 10)),
-			"has_point() with point located on right edge should return false.");
-	CHECK_MESSAGE(
-			rect.has_point(rect.position + Vector2i(10, 0)),
-			"has_point() with point located on top edge should return true.");
-	CHECK_MESSAGE(
-			!rect.has_point(rect.position + Vector2i(10, rect.size.y)),
-			"has_point() with point located on bottom edge should return false.");
-
-	/*
-	// FIXME: Disabled for now until GH-37617 is fixed one way or another.
-	// More tests should then be written like for the positive size case.
-	rect = Rect2i(0, 100, -1280, -720);
-	CHECK_MESSAGE(
-			rect.has_point(rect.position),
-			"has_point() with negative size should include `position`.");
-	CHECK_MESSAGE(
-			!rect.has_point(rect.position + rect.size),
-			"has_point() with negative size should not include `position + size`.");
-	*/
-
-	rect = Rect2i(-4000, -200, 1280, 720);
-	CHECK_MESSAGE(
-			rect.has_point(rect.position + Vector2i(0, 10)),
-			"has_point() with negative position and point located on left edge should return true.");
-	CHECK_MESSAGE(
-			!rect.has_point(rect.position + Vector2i(rect.size.x, 10)),
-			"has_point() with negative position and point located on right edge should return false.");
-	CHECK_MESSAGE(
-			rect.has_point(rect.position + Vector2i(10, 0)),
-			"has_point() with negative position and point located on top edge should return true.");
-	CHECK_MESSAGE(
-			!rect.has_point(rect.position + Vector2i(10, rect.size.y)),
-			"has_point() with negative position and point located on bottom edge should return false.");
-}
-
-TEST_CASE("[Rect2i] Intersection") {
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).intersects(Rect2i(0, 300, 100, 100)),
-			"intersects() with fully enclosed Rect2i should return the expected result.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).intersects(Rect2i(1200, 700, 100, 100)),
-			"intersects() with partially enclosed Rect2i should return the expected result.");
-	CHECK_MESSAGE(
-			!Rect2i(0, 100, 1280, 720).intersects(Rect2i(-4000, -4000, 100, 100)),
-			"intersects() with non-enclosed Rect2i should return the expected result.");
-	CHECK_MESSAGE(
-			!Rect2i(0, 0, 2, 2).intersects(Rect2i(2, 2, 2, 2)),
-			"intersects() with adjacent Rect2i should return the expected result.");
-}
-
-TEST_CASE("[Rect2i] Merging") {
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).merge(Rect2i(0, 300, 100, 100)) == Rect2i(0, 100, 1280, 720),
-			"merge() with fully enclosed Rect2i should return the expected result.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).merge(Rect2i(1200, 700, 100, 100)) == Rect2i(0, 100, 1300, 720),
-			"merge() with partially enclosed Rect2i should return the expected result.");
-	CHECK_MESSAGE(
-			Rect2i(0, 100, 1280, 720).merge(Rect2i(-4000, -4000, 100, 100)) == Rect2i(-4000, -4000, 5280, 4820),
-			"merge() with non-enclosed Rect2i should return the expected result.");
-}
 } // namespace TestRect2
 
 #endif // TEST_RECT2_H
diff --git a/tests/core/math/test_rect2i.h b/tests/core/math/test_rect2i.h
new file mode 100644
index 0000000000..0d1a088a66
--- /dev/null
+++ b/tests/core/math/test_rect2i.h
@@ -0,0 +1,311 @@
+/*************************************************************************/
+/*  test_rect2i.h                                                        */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2022 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_RECT2I_H
+#define TEST_RECT2I_H
+
+#include "core/math/rect2.h"
+#include "core/math/rect2i.h"
+
+#include "thirdparty/doctest/doctest.h"
+
+namespace TestRect2i {
+TEST_CASE("[Rect2i] Constructor methods") {
+	Rect2i recti = Rect2i(0, 100, 1280, 720);
+	Rect2i recti_vector = Rect2i(Vector2i(0, 100), Vector2i(1280, 720));
+	Rect2i recti_copy_recti = Rect2i(recti);
+	Rect2i recti_copy_rect = Rect2i(Rect2(0, 100, 1280, 720));
+
+	CHECK_MESSAGE(
+			recti == recti_vector,
+			"Rect2is created with the same dimensions but by different methods should be equal.");
+	CHECK_MESSAGE(
+			recti == recti_copy_recti,
+			"Rect2is created with the same dimensions but by different methods should be equal.");
+	CHECK_MESSAGE(
+			recti == recti_copy_rect,
+			"Rect2is created with the same dimensions but by different methods should be equal.");
+}
+
+TEST_CASE("[Rect2i] String conversion") {
+	// Note: This also depends on the Vector2 string representation.
+	CHECK_MESSAGE(
+			String(Rect2i(0, 100, 1280, 720)) == "[P: (0, 100), S: (1280, 720)]",
+			"The string representation should match the expected value.");
+}
+
+TEST_CASE("[Rect2i] Basic getters") {
+	const Rect2i rect = Rect2i(0, 100, 1280, 720);
+	CHECK_MESSAGE(
+			rect.get_position() == Vector2i(0, 100),
+			"get_position() should return the expected value.");
+	CHECK_MESSAGE(
+			rect.get_size() == Vector2i(1280, 720),
+			"get_size() should return the expected value.");
+	CHECK_MESSAGE(
+			rect.get_end() == Vector2i(1280, 820),
+			"get_end() should return the expected value.");
+	CHECK_MESSAGE(
+			rect.get_center() == Vector2i(640, 460),
+			"get_center() should return the expected value.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1281, 721).get_center() == Vector2i(640, 460),
+			"get_center() should return the expected value.");
+}
+
+TEST_CASE("[Rect2i] Basic setters") {
+	Rect2i rect = Rect2i(0, 100, 1280, 720);
+	rect.set_end(Vector2i(4000, 4000));
+	CHECK_MESSAGE(
+			rect == Rect2i(0, 100, 4000, 3900),
+			"set_end() should result in the expected Rect2i.");
+
+	rect = Rect2i(0, 100, 1280, 720);
+	rect.set_position(Vector2i(4000, 4000));
+	CHECK_MESSAGE(
+			rect == Rect2i(4000, 4000, 1280, 720),
+			"set_position() should result in the expected Rect2i.");
+
+	rect = Rect2i(0, 100, 1280, 720);
+	rect.set_size(Vector2i(4000, 4000));
+	CHECK_MESSAGE(
+			rect == Rect2i(0, 100, 4000, 4000),
+			"set_size() should result in the expected Rect2i.");
+}
+
+TEST_CASE("[Rect2i] Area getters") {
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).get_area() == 921'600,
+			"get_area() should return the expected value.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, -1280, -720).get_area() == 921'600,
+			"get_area() should return the expected value.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, -720).get_area() == -921'600,
+			"get_area() should return the expected value.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, -1280, 720).get_area() == -921'600,
+			"get_area() should return the expected value.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 0, 720).get_area() == 0,
+			"get_area() should return the expected value.");
+
+	CHECK_MESSAGE(
+			!Rect2i(0, 100, 1280, 720).has_no_area(),
+			"has_no_area() should return the expected value on Rect2i with an area.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 0, 500).has_no_area(),
+			"has_no_area() should return the expected value on Rect2i with no area.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 500, 0).has_no_area(),
+			"has_no_area() should return the expected value on Rect2i with no area.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 0, 0).has_no_area(),
+			"has_no_area() should return the expected value on Rect2i with no area.");
+}
+
+TEST_CASE("[Rect2i] Absolute coordinates") {
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).abs() == Rect2i(0, 100, 1280, 720),
+			"abs() should return the expected Rect2i.");
+	CHECK_MESSAGE(
+			Rect2i(0, -100, 1280, 720).abs() == Rect2i(0, -100, 1280, 720),
+			"abs() should return the expected Rect2i.");
+	CHECK_MESSAGE(
+			Rect2i(0, -100, -1280, -720).abs() == Rect2i(-1280, -820, 1280, 720),
+			"abs() should return the expected Rect2i.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, -1280, 720).abs() == Rect2i(-1280, 100, 1280, 720),
+			"abs() should return the expected Rect2i.");
+}
+
+TEST_CASE("[Rect2i] Intersection") {
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).intersection(Rect2i(0, 300, 100, 100)) == Rect2i(0, 300, 100, 100),
+			"intersection() with fully enclosed Rect2i should return the expected result.");
+	// The resulting Rect2i is 100 pixels high because the first Rect2i is vertically offset by 100 pixels.
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).intersection(Rect2i(1200, 700, 100, 100)) == Rect2i(1200, 700, 80, 100),
+			"intersection() with partially enclosed Rect2i should return the expected result.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).intersection(Rect2i(-4000, -4000, 100, 100)) == Rect2i(),
+			"intersection() with non-enclosed Rect2i should return the expected result.");
+}
+
+TEST_CASE("[Rect2i] Enclosing") {
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).encloses(Rect2i(0, 300, 100, 100)),
+			"encloses() with fully contained Rect2i should return the expected result.");
+	CHECK_MESSAGE(
+			!Rect2i(0, 100, 1280, 720).encloses(Rect2i(1200, 700, 100, 100)),
+			"encloses() with partially contained Rect2i should return the expected result.");
+	CHECK_MESSAGE(
+			!Rect2i(0, 100, 1280, 720).encloses(Rect2i(-4000, -4000, 100, 100)),
+			"encloses() with non-contained Rect2i should return the expected result.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).encloses(Rect2i(0, 100, 1280, 720)),
+			"encloses() with identical Rect2i should return the expected result.");
+}
+
+TEST_CASE("[Rect2i] Expanding") {
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).expand(Vector2i(500, 600)) == Rect2i(0, 100, 1280, 720),
+			"expand() with contained Vector2i should return the expected result.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).expand(Vector2i(0, 0)) == Rect2i(0, 0, 1280, 820),
+			"expand() with non-contained Vector2i should return the expected result.");
+}
+
+TEST_CASE("[Rect2i] Growing") {
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).grow(100) == Rect2i(-100, 0, 1480, 920),
+			"grow() with positive value should return the expected Rect2i.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).grow(-100) == Rect2i(100, 200, 1080, 520),
+			"grow() with negative value should return the expected Rect2i.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).grow(-4000) == Rect2i(4000, 4100, -6720, -7280),
+			"grow() with large negative value should return the expected Rect2i.");
+
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).grow_individual(100, 200, 300, 400) == Rect2i(-100, -100, 1680, 1320),
+			"grow_individual() with positive values should return the expected Rect2i.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).grow_individual(-100, 200, 300, -400) == Rect2i(100, -100, 1480, 520),
+			"grow_individual() with positive and negative values should return the expected Rect2i.");
+
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).grow_side(SIDE_TOP, 500) == Rect2i(0, -400, 1280, 1220),
+			"grow_side() with positive value should return the expected Rect2i.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).grow_side(SIDE_TOP, -500) == Rect2i(0, 600, 1280, 220),
+			"grow_side() with negative value should return the expected Rect2i.");
+}
+
+TEST_CASE("[Rect2i] Has point") {
+	Rect2i rect = Rect2i(0, 100, 1280, 720);
+	CHECK_MESSAGE(
+			rect.has_point(Vector2i(500, 600)),
+			"has_point() with contained Vector2i should return the expected result.");
+	CHECK_MESSAGE(
+			!rect.has_point(Vector2i(0, 0)),
+			"has_point() with non-contained Vector2i should return the expected result.");
+
+	CHECK_MESSAGE(
+			rect.has_point(rect.position),
+			"has_point() with positive size should include `position`.");
+	CHECK_MESSAGE(
+			rect.has_point(rect.position + Vector2i(1, 1)),
+			"has_point() with positive size should include `position + (1, 1)`.");
+	CHECK_MESSAGE(
+			!rect.has_point(rect.position + Vector2i(1, -1)),
+			"has_point() with positive size should not include `position + (1, -1)`.");
+	CHECK_MESSAGE(
+			!rect.has_point(rect.position + rect.size),
+			"has_point() with positive size should not include `position + size`.");
+	CHECK_MESSAGE(
+			!rect.has_point(rect.position + rect.size + Vector2i(1, 1)),
+			"has_point() with positive size should not include `position + size + (1, 1)`.");
+	CHECK_MESSAGE(
+			rect.has_point(rect.position + rect.size + Vector2i(-1, -1)),
+			"has_point() with positive size should include `position + size + (-1, -1)`.");
+	CHECK_MESSAGE(
+			!rect.has_point(rect.position + rect.size + Vector2i(-1, 1)),
+			"has_point() with positive size should not include `position + size + (-1, 1)`.");
+
+	CHECK_MESSAGE(
+			rect.has_point(rect.position + Vector2i(0, 10)),
+			"has_point() with point located on left edge should return true.");
+	CHECK_MESSAGE(
+			!rect.has_point(rect.position + Vector2i(rect.size.x, 10)),
+			"has_point() with point located on right edge should return false.");
+	CHECK_MESSAGE(
+			rect.has_point(rect.position + Vector2i(10, 0)),
+			"has_point() with point located on top edge should return true.");
+	CHECK_MESSAGE(
+			!rect.has_point(rect.position + Vector2i(10, rect.size.y)),
+			"has_point() with point located on bottom edge should return false.");
+
+	/*
+	// FIXME: Disabled for now until GH-37617 is fixed one way or another.
+	// More tests should then be written like for the positive size case.
+	rect = Rect2i(0, 100, -1280, -720);
+	CHECK_MESSAGE(
+			rect.has_point(rect.position),
+			"has_point() with negative size should include `position`.");
+	CHECK_MESSAGE(
+			!rect.has_point(rect.position + rect.size),
+			"has_point() with negative size should not include `position + size`.");
+	*/
+
+	rect = Rect2i(-4000, -200, 1280, 720);
+	CHECK_MESSAGE(
+			rect.has_point(rect.position + Vector2i(0, 10)),
+			"has_point() with negative position and point located on left edge should return true.");
+	CHECK_MESSAGE(
+			!rect.has_point(rect.position + Vector2i(rect.size.x, 10)),
+			"has_point() with negative position and point located on right edge should return false.");
+	CHECK_MESSAGE(
+			rect.has_point(rect.position + Vector2i(10, 0)),
+			"has_point() with negative position and point located on top edge should return true.");
+	CHECK_MESSAGE(
+			!rect.has_point(rect.position + Vector2i(10, rect.size.y)),
+			"has_point() with negative position and point located on bottom edge should return false.");
+}
+
+TEST_CASE("[Rect2i] Intersection") {
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).intersects(Rect2i(0, 300, 100, 100)),
+			"intersects() with fully enclosed Rect2i should return the expected result.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).intersects(Rect2i(1200, 700, 100, 100)),
+			"intersects() with partially enclosed Rect2i should return the expected result.");
+	CHECK_MESSAGE(
+			!Rect2i(0, 100, 1280, 720).intersects(Rect2i(-4000, -4000, 100, 100)),
+			"intersects() with non-enclosed Rect2i should return the expected result.");
+	CHECK_MESSAGE(
+			!Rect2i(0, 0, 2, 2).intersects(Rect2i(2, 2, 2, 2)),
+			"intersects() with adjacent Rect2i should return the expected result.");
+}
+
+TEST_CASE("[Rect2i] Merging") {
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).merge(Rect2i(0, 300, 100, 100)) == Rect2i(0, 100, 1280, 720),
+			"merge() with fully enclosed Rect2i should return the expected result.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).merge(Rect2i(1200, 700, 100, 100)) == Rect2i(0, 100, 1300, 720),
+			"merge() with partially enclosed Rect2i should return the expected result.");
+	CHECK_MESSAGE(
+			Rect2i(0, 100, 1280, 720).merge(Rect2i(-4000, -4000, 100, 100)) == Rect2i(-4000, -4000, 5280, 4820),
+			"merge() with non-enclosed Rect2i should return the expected result.");
+}
+} // namespace TestRect2i
+
+#endif // TEST_RECT2I_H
diff --git a/tests/test_main.cpp b/tests/test_main.cpp
index 0190fa5184..3b51a6d805 100644
--- a/tests/test_main.cpp
+++ b/tests/test_main.cpp
@@ -48,6 +48,7 @@
 #include "tests/core/math/test_math.h"
 #include "tests/core/math/test_random_number_generator.h"
 #include "tests/core/math/test_rect2.h"
+#include "tests/core/math/test_rect2i.h"
 #include "tests/core/math/test_vector2.h"
 #include "tests/core/math/test_vector2i.h"
 #include "tests/core/math/test_vector3.h"