diff --git a/tests/scene/test_split_container.h b/tests/scene/test_split_container.h
new file mode 100644
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--- /dev/null
+++ b/tests/scene/test_split_container.h
@@ -0,0 +1,1480 @@
+/**************************************************************************/
+/*  test_split_container.h                                                */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* 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_SPLIT_CONTAINER_H
+#define TEST_SPLIT_CONTAINER_H
+
+#include "scene/gui/split_container.h"
+#include "scene/main/window.h"
+
+#include "tests/test_macros.h"
+
+namespace TestSplitContainer {
+
+static inline void check_positions(SplitContainer *p_sc, const Vector<int> &p_positions, int p_sep, bool p_horizontal = true) {
+	// Checks the rects of each split container child.
+	CHECK(p_sc->get_child_count(false) == p_positions.size() + 1);
+	int last_pos = 0;
+	for (int i = 0; i < p_sc->get_child_count(false); i++) {
+		// Assuming there is no invalid children.
+		Control *c = Object::cast_to<Control>(p_sc->get_child(i, false));
+		int pos = i >= p_positions.size() ? p_sc->get_size()[p_horizontal ? 0 : 1] : p_positions[i];
+		Rect2 rect;
+		if (p_horizontal) {
+			rect.size.y = p_sc->get_size().y;
+			rect.position.x = last_pos;
+			rect.size.x = pos - last_pos;
+		} else {
+			rect.size.x = p_sc->get_size().x;
+			rect.position.y = last_pos;
+			rect.size.y = pos - last_pos;
+		}
+		CHECK_MESSAGE(c->get_rect() == rect, vformat("Child %s is the wrong size.", i));
+		last_pos = pos + p_sep;
+	}
+}
+
+static inline void check_position(SplitContainer *p_sc, int p_position, int p_sep, bool p_horizontal = true) {
+	check_positions(p_sc, { p_position }, p_sep, p_horizontal);
+}
+
+static inline void check_positions_rtl(SplitContainer *p_sc, const Vector<int> &p_positions, int p_sep) {
+	// Checks the rects of each split container child. Right to left layout.
+	CHECK(p_sc->get_child_count(false) == p_positions.size() + 1);
+	int last_pos = p_sc->get_size().x;
+	for (int i = 0; i < p_sc->get_child_count(false); i++) {
+		// Assuming there is no invalid children.
+		Control *c = Object::cast_to<Control>(p_sc->get_child(i, false));
+		int pos = i >= p_positions.size() ? 0 : p_sc->get_size().x - p_positions[i];
+		Rect2 rect;
+		rect.size.y = p_sc->get_size().y;
+		rect.position.x = pos;
+		rect.size.x = last_pos - pos;
+		CHECK_MESSAGE(c->get_rect() == rect, vformat("Child %s is the wrong size.", i));
+		last_pos = pos - p_sep;
+	}
+}
+
+static inline void check_position_rtl(SplitContainer *p_sc, int p_position, int p_sep) {
+	check_positions_rtl(p_sc, { p_position }, p_sep);
+}
+
+TEST_CASE("[SceneTree][SplitContainer] Add children") {
+	SplitContainer *split_container = memnew(SplitContainer);
+	split_container->set_size(Size2(500, 500));
+	SceneTree::get_singleton()->get_root()->add_child(split_container);
+
+	SUBCASE("[SplitContainer] One child") {
+		Control *child_a = memnew(Control);
+		split_container->add_child(child_a);
+		MessageQueue::get_singleton()->flush();
+
+		// One child will fill the entire area.
+		CHECK(child_a->get_rect() == split_container->get_rect());
+
+		split_container->set_vertical(true);
+		CHECK(child_a->get_rect() == split_container->get_rect());
+
+		memdelete(child_a);
+	}
+
+	SUBCASE("[SplitContainer] Preserve split offset") {
+		// The split offset is preserved through adding, removing, and changing visibility of children.
+		split_container->set_split_offset(100);
+		CHECK(split_container->get_split_offset() == 100);
+
+		Control *child_a = memnew(Control);
+		split_container->add_child(child_a);
+		MessageQueue::get_singleton()->flush();
+		CHECK(split_container->get_split_offset() == 100);
+
+		Control *child_b = memnew(Control);
+		split_container->add_child(child_b);
+		MessageQueue::get_singleton()->flush();
+		CHECK(split_container->get_split_offset() == 100);
+
+		child_a->hide();
+		MessageQueue::get_singleton()->flush();
+		CHECK(split_container->get_split_offset() == 100);
+
+		child_b->hide();
+		MessageQueue::get_singleton()->flush();
+		CHECK(split_container->get_split_offset() == 100);
+
+		child_b->show();
+		MessageQueue::get_singleton()->flush();
+		CHECK(split_container->get_split_offset() == 100);
+
+		child_a->show();
+		MessageQueue::get_singleton()->flush();
+		CHECK(split_container->get_split_offset() == 100);
+
+		split_container->remove_child(child_a);
+		MessageQueue::get_singleton()->flush();
+		CHECK(split_container->get_split_offset() == 100);
+
+		split_container->add_child(child_a);
+		MessageQueue::get_singleton()->flush();
+		CHECK(split_container->get_split_offset() == 100);
+
+		memdelete(child_a);
+		memdelete(child_b);
+	}
+
+	memdelete(split_container);
+}
+
+TEST_CASE("[SceneTree][SplitContainer] Dragger visibility") {
+	SplitContainer *split_container = memnew(SplitContainer);
+	split_container->set_size(Size2(500, 500));
+	SceneTree::get_singleton()->get_root()->add_child(split_container);
+	Control *child_a = memnew(Control);
+	Control *child_b = memnew(Control);
+	split_container->add_child(child_a);
+	split_container->add_child(child_b);
+	SplitContainerDragger *dragger = Object::cast_to<SplitContainerDragger>(split_container->get_child(2, true));
+
+	split_container->add_theme_constant_override("autohide", 0);
+	MessageQueue::get_singleton()->flush();
+
+	const int sep_constant = split_container->get_theme_constant("separation");
+	const Size2i separator_size = Size2i(MAX(sep_constant, split_container->get_theme_icon("h_grabber")->get_width()), MAX(sep_constant, split_container->get_theme_icon("v_grabber")->get_height()));
+
+	SUBCASE("[SplitContainer] Visibility based on child count") {
+		split_container->remove_child(child_a);
+		split_container->remove_child(child_b);
+		MessageQueue::get_singleton()->flush();
+
+		// No children, not visible.
+		CHECK_FALSE(dragger->is_visible());
+
+		// Add one child, not visible.
+		split_container->add_child(child_a);
+		MessageQueue::get_singleton()->flush();
+		CHECK_FALSE(dragger->is_visible());
+
+		// Two children, visible.
+		split_container->add_child(child_b);
+		MessageQueue::get_singleton()->flush();
+		CHECK(dragger->is_visible());
+
+		// Remove a child, not visible.
+		split_container->remove_child(child_b);
+		MessageQueue::get_singleton()->flush();
+		CHECK_FALSE(dragger->is_visible());
+	}
+
+	SUBCASE("[SplitContainer] Set dragger visibility") {
+		split_container->set_dragger_visibility(SplitContainer::DRAGGER_HIDDEN);
+		MessageQueue::get_singleton()->flush();
+		check_position(split_container, 0, separator_size.x);
+		// Can't check the visibility since it happens in draw.
+
+		split_container->set_dragger_visibility(SplitContainer::DRAGGER_HIDDEN_COLLAPSED);
+		MessageQueue::get_singleton()->flush();
+		check_position(split_container, 0, 0);
+
+		split_container->set_dragger_visibility(SplitContainer::DRAGGER_VISIBLE);
+		MessageQueue::get_singleton()->flush();
+		check_position(split_container, 0, separator_size.x);
+	}
+
+	SUBCASE("[SplitContainer] Not visible when collapsed") {
+		split_container->set_collapsed(true);
+		MessageQueue::get_singleton()->flush();
+		CHECK_FALSE(dragger->is_visible());
+
+		split_container->set_collapsed(false);
+		MessageQueue::get_singleton()->flush();
+		CHECK(dragger->is_visible());
+	}
+
+	memdelete(child_a);
+	memdelete(child_b);
+	memdelete(split_container);
+}
+
+TEST_CASE("[SceneTree][SplitContainer] Collapsed") {
+	DisplayServerMock *DS = (DisplayServerMock *)(DisplayServer::get_singleton());
+
+	SplitContainer *split_container = memnew(SplitContainer);
+	split_container->set_size(Size2(500, 500));
+	SceneTree::get_singleton()->get_root()->add_child(split_container);
+	Control *child_a = memnew(Control);
+	split_container->add_child(child_a);
+	Control *child_b = memnew(Control);
+	split_container->add_child(child_b);
+	MessageQueue::get_singleton()->flush();
+
+	const int sep_constant = split_container->get_theme_constant("separation");
+	const Size2i separator_size = Size2i(MAX(sep_constant, split_container->get_theme_icon("h_grabber")->get_width()), MAX(sep_constant, split_container->get_theme_icon("v_grabber")->get_height()));
+
+	SUBCASE("[SplitContainer] Dragging and cursor") {
+		split_container->set_collapsed(true);
+
+		// Cursor is default.
+		SEND_GUI_MOUSE_MOTION_EVENT(Point2(1, 1), MouseButtonMask::NONE, Key::NONE);
+		CHECK(DS->get_cursor_shape() == DisplayServer::CURSOR_ARROW);
+
+		// Dragger is disabled, cannot drag.
+		SEND_GUI_MOUSE_BUTTON_EVENT(Point2(1, 1), MouseButton::LEFT, MouseButtonMask::LEFT, Key::NONE);
+		MessageQueue::get_singleton()->flush();
+		check_position(split_container, 0, separator_size.x);
+		CHECK(split_container->get_split_offset() == 0);
+		SEND_GUI_MOUSE_MOTION_EVENT(Point2(10, 1), MouseButtonMask::LEFT, Key::NONE);
+		MessageQueue::get_singleton()->flush();
+		check_position(split_container, 0, separator_size.x);
+		CHECK(split_container->get_split_offset() == 0);
+	}
+
+	SUBCASE("[SplitContainer] No expand flags") {
+		int def_pos = 0;
+
+		split_container->set_split_offset(10);
+		MessageQueue::get_singleton()->flush();
+		check_position(split_container, def_pos + 10, separator_size.x);
+
+		split_container->set_collapsed(true);
+		MessageQueue::get_singleton()->flush();
+
+		// The split offset is treated as 0 when collapsed.
+		check_position(split_container, def_pos, separator_size.x);
+		CHECK(split_container->get_split_offset() == 10);
+	}
+
+	SUBCASE("[SplitContainer] First child expanded") {
+		int def_pos = split_container->get_size().x - separator_size.x;
+		child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+		split_container->set_split_offset(-10);
+		MessageQueue::get_singleton()->flush();
+
+		check_position(split_container, def_pos - 10, separator_size.x);
+
+		split_container->set_collapsed(true);
+		MessageQueue::get_singleton()->flush();
+
+		// The split offset is treated as 0 when collapsed.
+		check_position(split_container, def_pos, separator_size.x);
+		CHECK(split_container->get_split_offset() == -10);
+	}
+
+	SUBCASE("[SplitContainer] Second child expanded") {
+		int def_pos = 0;
+		child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+		split_container->set_split_offset(10);
+		MessageQueue::get_singleton()->flush();
+
+		check_position(split_container, def_pos + 10, separator_size.x);
+
+		split_container->set_collapsed(true);
+		MessageQueue::get_singleton()->flush();
+
+		// The split offset is treated as 0 when collapsed.
+		check_position(split_container, def_pos, separator_size.x);
+		CHECK(split_container->get_split_offset() == 10);
+	}
+
+	SUBCASE("[SplitContainer] Both children expanded") {
+		int def_pos = (split_container->get_size().y - separator_size.y) / 2;
+		child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+		child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+		split_container->set_split_offset(10);
+		MessageQueue::get_singleton()->flush();
+
+		check_position(split_container, def_pos + 10, separator_size.x);
+
+		split_container->set_collapsed(true);
+		MessageQueue::get_singleton()->flush();
+
+		// The split offset is treated as 0 when collapsed.
+		check_position(split_container, def_pos, separator_size.x);
+		CHECK(split_container->get_split_offset() == 10);
+	}
+
+	memdelete(child_a);
+	memdelete(child_b);
+	memdelete(split_container);
+}
+
+TEST_CASE("[SceneTree][SplitContainer] Cursor shape") {
+	DisplayServerMock *DS = (DisplayServerMock *)(DisplayServer::get_singleton());
+
+	SplitContainer *split_container = memnew(SplitContainer);
+	split_container->set_size(Size2(500, 500));
+	SceneTree::get_singleton()->get_root()->add_child(split_container);
+	Control *child_a = memnew(Control);
+	split_container->add_child(child_a);
+	Control *child_b = memnew(Control);
+	split_container->add_child(child_b);
+	MessageQueue::get_singleton()->flush();
+
+	Point2 on_dragger = Point2(1, 1);
+	Point2 not_on_dragger = Point2(50, 50);
+
+	// Default cursor shape.
+	SEND_GUI_MOUSE_MOTION_EVENT(not_on_dragger, MouseButtonMask::NONE, Key::NONE);
+	CHECK(DS->get_cursor_shape() == DisplayServer::CURSOR_ARROW);
+
+	// Horizontal cursor shape.
+	SEND_GUI_MOUSE_MOTION_EVENT(on_dragger, MouseButtonMask::NONE, Key::NONE);
+	CHECK(DS->get_cursor_shape() == DisplayServer::CURSOR_HSPLIT);
+
+	// Vertical cursor shape.
+	split_container->set_vertical(true);
+	SEND_GUI_MOUSE_MOTION_EVENT(on_dragger, MouseButtonMask::NONE, Key::NONE);
+	CHECK(DS->get_cursor_shape() == DisplayServer::CURSOR_VSPLIT);
+
+	// Move off, default cursor shape.
+	SEND_GUI_MOUSE_MOTION_EVENT(not_on_dragger, MouseButtonMask::NONE, Key::NONE);
+	CHECK(DS->get_cursor_shape() == DisplayServer::CURSOR_ARROW);
+
+	memdelete(child_a);
+	memdelete(child_b);
+	memdelete(split_container);
+}
+
+TEST_CASE("[SceneTree][SplitContainer] Two children") {
+	SplitContainer *split_container = memnew(SplitContainer);
+	split_container->set_size(Size2(500, 500));
+	SceneTree::get_singleton()->get_root()->add_child(split_container);
+	Control *child_a = memnew(Control);
+	Control *child_b = memnew(Control);
+	split_container->add_child(child_a);
+	split_container->add_child(child_b);
+	MessageQueue::get_singleton()->flush();
+
+	const int sep_constant = split_container->get_theme_constant("separation");
+	const Size2i separator_size = Size2i(MAX(sep_constant, split_container->get_theme_icon("h_grabber")->get_width()), MAX(sep_constant, split_container->get_theme_icon("v_grabber")->get_height()));
+
+	SUBCASE("[SplitContainer] Minimum size") {
+		// Minimum size is the sum of both children's minimum sizes and the separator depending on the vertical axis.
+		child_a->set_custom_minimum_size(Size2(100, 200));
+		child_b->set_custom_minimum_size(Size2(100, 200));
+		MessageQueue::get_singleton()->flush();
+
+		Size2 min_size = split_container->get_minimum_size();
+		CHECK(min_size.x == 200 + separator_size.x);
+		CHECK(min_size.y == 200);
+
+		split_container->set_vertical(true);
+		MessageQueue::get_singleton()->flush();
+		min_size = split_container->get_minimum_size();
+		CHECK(min_size.x == 100);
+		CHECK(min_size.y == 400 + separator_size.y);
+	}
+
+	SUBCASE("[SplitContainer] Default position") {
+		SUBCASE("[SplitContainer] Vertical") {
+			// Make sure clamping the split offset doesn't change it or the position.
+			split_container->set_vertical(true);
+
+			// No expand flags set.
+			MessageQueue::get_singleton()->flush();
+			int def_pos = 0;
+			check_position(split_container, def_pos, separator_size.y, false);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 0);
+			check_position(split_container, def_pos, separator_size.y, false);
+
+			// First expand flags set.
+			child_a->set_v_size_flags(Control::SIZE_EXPAND_FILL);
+			child_b->set_v_size_flags(Control::SIZE_FILL);
+			MessageQueue::get_singleton()->flush();
+			def_pos = split_container->get_size().y - separator_size.y;
+			check_position(split_container, def_pos, separator_size.y, false);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 0);
+			check_position(split_container, def_pos, separator_size.y, false);
+
+			// Second expand flags set.
+			child_a->set_v_size_flags(Control::SIZE_FILL);
+			child_b->set_v_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+			def_pos = 0;
+			check_position(split_container, 0, separator_size.y, false);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 0);
+			check_position(split_container, def_pos, separator_size.y, false);
+
+			// Both expand flags set.
+			child_a->set_v_size_flags(Control::SIZE_EXPAND_FILL);
+			child_b->set_v_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+			def_pos = (split_container->get_size().y - separator_size.y) / 2;
+			check_position(split_container, def_pos, separator_size.y, false);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 0);
+			check_position(split_container, def_pos, separator_size.y, false);
+
+			// Unequal stretch ratios.
+			child_a->set_stretch_ratio(2.0);
+			MessageQueue::get_singleton()->flush();
+			def_pos = (split_container->get_size().y * 2 / 3) - separator_size.y / 2;
+			check_position(split_container, def_pos, separator_size.y, false);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 0);
+			check_position(split_container, def_pos, separator_size.y, false);
+		}
+
+		SUBCASE("[SplitContainer] Right to left") {
+			split_container->set_layout_direction(Control::LAYOUT_DIRECTION_RTL);
+			split_container->set_position(Point2(0, 0));
+
+			// No expand flags set.
+			MessageQueue::get_singleton()->flush();
+			int def_pos = 0;
+			check_position_rtl(split_container, def_pos, separator_size.y);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 0);
+			check_position_rtl(split_container, def_pos, separator_size.y);
+
+			// First expand flags set.
+			child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			child_b->set_h_size_flags(Control::SIZE_FILL);
+			MessageQueue::get_singleton()->flush();
+			def_pos = split_container->get_size().y - separator_size.y;
+			check_position_rtl(split_container, def_pos, separator_size.y);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 0);
+			check_position_rtl(split_container, def_pos, separator_size.y);
+
+			// Second expand flags set.
+			child_a->set_h_size_flags(Control::SIZE_FILL);
+			child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+			def_pos = 0;
+			check_position_rtl(split_container, 0, separator_size.y);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 0);
+			check_position_rtl(split_container, def_pos, separator_size.y);
+
+			// Both expand flags set.
+			child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+			def_pos = (split_container->get_size().y - separator_size.y) / 2;
+			check_position_rtl(split_container, def_pos, separator_size.y);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 0);
+			check_position_rtl(split_container, def_pos, separator_size.y);
+
+			// Unequal stretch ratios.
+			child_a->set_stretch_ratio(2.0);
+			MessageQueue::get_singleton()->flush();
+			def_pos = (split_container->get_size().y * 2 / 3) - separator_size.y / 2;
+			check_position_rtl(split_container, def_pos, separator_size.y);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 0);
+			check_position_rtl(split_container, def_pos, separator_size.y);
+		}
+
+		SUBCASE("[SplitContainer] No expand flags") {
+			int def_pos = 0;
+
+			check_position(split_container, def_pos, separator_size.x);
+
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 0);
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Minimum sizes affect default position.
+
+			// First child with minimum size.
+			child_a->set_custom_minimum_size(Size2(400, 0));
+			MessageQueue::get_singleton()->flush();
+			def_pos = 400;
+			check_position(split_container, def_pos, separator_size.x);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == def_pos);
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Second child with minimum size.
+			child_a->set_custom_minimum_size(Size2(0, 0));
+			child_b->set_custom_minimum_size(Size2(400, 0));
+			MessageQueue::get_singleton()->flush();
+			def_pos = split_container->get_size().x - 400 - separator_size.x;
+			check_position(split_container, def_pos, separator_size.x);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == def_pos);
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Both children with minimum size.
+			child_a->set_custom_minimum_size(Size2(200, 0));
+			child_b->set_custom_minimum_size(Size2(288, 0));
+			MessageQueue::get_singleton()->flush();
+			def_pos = 200;
+			check_position(split_container, def_pos, separator_size.x);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == def_pos);
+			check_position(split_container, def_pos, separator_size.x);
+		}
+
+		SUBCASE("[SplitContainer] First child expanded") {
+			const int def_pos = split_container->get_size().x - separator_size.x;
+			child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+
+			check_position(split_container, def_pos, separator_size.x);
+
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 0);
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Minimum sizes affect default position.
+
+			// First child with minimum size.
+			child_a->set_custom_minimum_size(Size2(400, 0));
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos, separator_size.x);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 0);
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Second child with minimum size.
+			child_a->set_custom_minimum_size(Size2(0, 0));
+			child_b->set_custom_minimum_size(Size2(400, 0));
+			MessageQueue::get_singleton()->flush();
+			int pos = split_container->get_size().x - 400 - separator_size.x;
+			check_position(split_container, pos, separator_size.x);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == pos - def_pos);
+			check_position(split_container, pos, separator_size.x);
+
+			// Both children with minimum size.
+			child_a->set_custom_minimum_size(Size2(200, 0));
+			child_b->set_custom_minimum_size(Size2(288, 0));
+			MessageQueue::get_singleton()->flush();
+			pos = 200;
+			check_position(split_container, pos, separator_size.x);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == pos - def_pos);
+			check_position(split_container, pos, separator_size.x);
+		}
+
+		SUBCASE("[SplitContainer] Second child expanded") {
+			int def_pos = 0;
+			child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+
+			check_position(split_container, def_pos, separator_size.x);
+
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 0);
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Minimum sizes affect default position.
+
+			// First child with minimum size.
+			child_a->set_custom_minimum_size(Size2(400, 0));
+			MessageQueue::get_singleton()->flush();
+			def_pos = 400;
+			check_position(split_container, def_pos, separator_size.x);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == def_pos);
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Second child with minimum size.
+			child_a->set_custom_minimum_size(Size2(0, 0));
+			child_b->set_custom_minimum_size(Size2(400, 0));
+			MessageQueue::get_singleton()->flush();
+			def_pos = 500 - 400 - separator_size.x;
+			check_position(split_container, def_pos, separator_size.x);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == def_pos);
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Both children with minimum size.
+			child_a->set_custom_minimum_size(Size2(200, 0));
+			child_b->set_custom_minimum_size(Size2(288, 0));
+			MessageQueue::get_singleton()->flush();
+			def_pos = 200;
+			check_position(split_container, def_pos, separator_size.x);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == def_pos);
+			check_position(split_container, def_pos, separator_size.x);
+		}
+
+		SUBCASE("[SplitContainer] Both children expanded") {
+			const int def_pos = (split_container->get_size().x - separator_size.x) / 2;
+			child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+
+			check_position(split_container, def_pos, separator_size.x);
+
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 0);
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Minimum sizes affect default position.
+
+			// First child with minimum size.
+			child_a->set_custom_minimum_size(Size2(400, 0));
+			MessageQueue::get_singleton()->flush();
+			int pos = 400;
+			check_position(split_container, pos, separator_size.x);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == pos - def_pos);
+			check_position(split_container, pos, separator_size.x);
+
+			// Second child with minimum size.
+			child_a->set_custom_minimum_size(Size2(0, 0));
+			child_b->set_custom_minimum_size(Size2(400, 0));
+			MessageQueue::get_singleton()->flush();
+			pos = split_container->get_size().x - 400 - separator_size.x;
+			check_position(split_container, pos, separator_size.x);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == pos - def_pos);
+			check_position(split_container, pos, separator_size.x);
+
+			// Both children with minimum size.
+			child_a->set_custom_minimum_size(Size2(200, 0));
+			child_b->set_custom_minimum_size(Size2(288, 0));
+			MessageQueue::get_singleton()->flush();
+			pos = 200;
+			check_position(split_container, pos, separator_size.x);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == pos - def_pos);
+			check_position(split_container, pos, separator_size.x);
+		}
+
+		SUBCASE("[SplitContainer] Unequal stretch ratios") {
+			const int def_pos = (split_container->get_size().x * 2 / 3) - separator_size.x / 2;
+			child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			child_a->set_stretch_ratio(2.0);
+			MessageQueue::get_singleton()->flush();
+
+			check_position(split_container, def_pos, separator_size.x);
+
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 0);
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Minimum sizes affect default position.
+
+			// First child with minimum size.
+			child_a->set_custom_minimum_size(Size2(400, 0));
+			MessageQueue::get_singleton()->flush();
+			int pos = 400;
+			check_position(split_container, pos, separator_size.x);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == pos - def_pos);
+			check_position(split_container, pos, separator_size.x);
+
+			// Second child with minimum size.
+			child_a->set_custom_minimum_size(Size2(0, 0));
+			child_b->set_custom_minimum_size(Size2(400, 0));
+			MessageQueue::get_singleton()->flush();
+			pos = split_container->get_size().x - 400 - separator_size.x;
+			check_position(split_container, pos, separator_size.x);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == pos - def_pos);
+			check_position(split_container, pos, separator_size.x);
+
+			// Both children with minimum size.
+			child_a->set_custom_minimum_size(Size2(200, 0));
+			child_b->set_custom_minimum_size(Size2(288, 0));
+			MessageQueue::get_singleton()->flush();
+			pos = 200;
+			check_position(split_container, pos, separator_size.x);
+			split_container->clamp_split_offset();
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == pos - def_pos);
+			check_position(split_container, pos, separator_size.x);
+		}
+	}
+
+	SUBCASE("[SplitContainer] Set split offset") {
+		SUBCASE("[SplitContainer] Right to left") {
+			split_container->set_layout_direction(Control::LAYOUT_DIRECTION_RTL);
+			split_container->set_position(Point2(0, 0));
+			int def_pos = 0;
+			// Positive.
+			split_container->set_split_offset(10);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 10);
+			check_position_rtl(split_container, def_pos + 10, separator_size.x);
+
+			// Negative.
+			split_container->set_split_offset(-10);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == -10);
+			check_position_rtl(split_container, def_pos, separator_size.x);
+		}
+
+		SUBCASE("[SplitContainer] No expand flags") {
+			int def_pos = 0;
+
+			// Positive.
+			split_container->set_split_offset(10);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 10);
+			check_position(split_container, def_pos + 10, separator_size.x);
+
+			// Negative.
+			split_container->set_split_offset(-10);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == -10);
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Clamped.
+			split_container->set_split_offset(1000);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 1000);
+			check_position(split_container, split_container->get_size().x - separator_size.x, separator_size.x);
+		}
+
+		SUBCASE("[SplitContainer] First child expanded") {
+			int def_pos = split_container->get_size().x - separator_size.x;
+			child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+
+			// Positive.
+			split_container->set_split_offset(10);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 10);
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Negative.
+			split_container->set_split_offset(-10);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == -10);
+			check_position(split_container, def_pos - 10, separator_size.x);
+
+			// Clamped.
+			split_container->set_split_offset(-1000);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == -1000);
+			check_position(split_container, 0, separator_size.x);
+		}
+
+		SUBCASE("[SplitContainer] Second child expanded") {
+			int def_pos = 0;
+			child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+
+			// Positive.
+			split_container->set_split_offset(10);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 10);
+			check_position(split_container, def_pos + 10, separator_size.x);
+
+			// Negative.
+			split_container->set_split_offset(-10);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == -10);
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Clamped.
+			split_container->set_split_offset(1000);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 1000);
+			check_position(split_container, split_container->get_size().x - separator_size.x, separator_size.x);
+		}
+
+		SUBCASE("[SplitContainer] Both children expanded") {
+			int def_pos = (split_container->get_size().x - separator_size.x) / 2;
+			child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+
+			// Positive.
+			split_container->set_split_offset(10);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 10);
+			check_position(split_container, def_pos + 10, separator_size.x);
+
+			// Negative.
+			split_container->set_split_offset(-10);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == -10);
+			check_position(split_container, def_pos - 10, separator_size.x);
+
+			// Clamped positive.
+			split_container->set_split_offset(1000);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 1000);
+			check_position(split_container, split_container->get_size().x - separator_size.x, separator_size.x);
+
+			// Clamped negative.
+			split_container->set_split_offset(-1000);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == -1000);
+			check_position(split_container, 0, separator_size.x);
+		}
+
+		SUBCASE("[SplitContainer] Unequal stretch ratios") {
+			int def_pos = (split_container->get_size().x * 2 / 3) - separator_size.x / 2;
+			child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			child_a->set_stretch_ratio(2.0);
+			MessageQueue::get_singleton()->flush();
+
+			// Positive.
+			split_container->set_split_offset(10);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 10);
+			check_position(split_container, def_pos + 10, separator_size.x);
+
+			// Negative.
+			split_container->set_split_offset(-10);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == -10);
+			check_position(split_container, def_pos - 10, separator_size.x);
+
+			// Clamped positive.
+			split_container->set_split_offset(1000);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 1000);
+			check_position(split_container, split_container->get_size().x - separator_size.x, separator_size.x);
+
+			// Clamped negative.
+			split_container->set_split_offset(-1000);
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == -1000);
+			check_position(split_container, 0, separator_size.x);
+		}
+	}
+
+	SUBCASE("[SplitContainer] Keep split offset when changing minimum size") {
+		SUBCASE("[SplitContainer] No expand flags") {
+			int def_pos = 0;
+
+			split_container->set_split_offset(100);
+			child_a->set_custom_minimum_size(Size2(10, 0));
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 100);
+			check_position(split_container, def_pos + 100, separator_size.x);
+
+			child_a->set_custom_minimum_size(Size2(50, 0));
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 100);
+			check_position(split_container, def_pos + 100, separator_size.x);
+		}
+
+		SUBCASE("[SplitContainer] First child expanded") {
+			int def_pos = split_container->get_size().x - separator_size.x;
+			child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+
+			split_container->set_split_offset(-100);
+			child_b->set_custom_minimum_size(Size2(10, 0));
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == -100);
+			check_position(split_container, def_pos - 100, separator_size.x);
+
+			child_b->set_custom_minimum_size(Size2(50, 0));
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == -100);
+			check_position(split_container, def_pos - 100, separator_size.x);
+		}
+
+		SUBCASE("[SplitContainer] Second child expanded") {
+			int def_pos = 0;
+			child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+
+			split_container->set_split_offset(100);
+			child_a->set_custom_minimum_size(Size2(10, 0));
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 100);
+			check_position(split_container, def_pos + 100, separator_size.x);
+
+			child_a->set_custom_minimum_size(Size2(50, 0));
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 100);
+			check_position(split_container, def_pos + 100, separator_size.x);
+		}
+
+		SUBCASE("[SplitContainer] Both children expanded") {
+			int def_pos = (split_container->get_size().x - separator_size.x) / 2;
+			child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+
+			split_container->set_split_offset(20);
+			child_a->set_custom_minimum_size(Size2(10, 0));
+			child_b->set_custom_minimum_size(Size2(10, 0));
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 20);
+			check_position(split_container, def_pos + 20, separator_size.x);
+
+			child_a->set_custom_minimum_size(Size2(50, 0));
+			child_b->set_custom_minimum_size(Size2(50, 0));
+			MessageQueue::get_singleton()->flush();
+			CHECK(split_container->get_split_offset() == 20);
+			check_position(split_container, def_pos + 20, separator_size.x);
+		}
+	}
+
+	SUBCASE("[SplitContainer] Resize split container") {
+		SUBCASE("[SplitContainer] No expand flags") {
+			int def_pos = 0;
+			// Increase the size.
+			split_container->set_size(Size2(600, 500));
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Decrease the size.
+			split_container->set_size(Size2(400, 500));
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Change size with a split offset.
+			split_container->set_split_offset(100);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos + 100, separator_size.x);
+
+			split_container->set_size(Size2(500, 500));
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos + 100, separator_size.x);
+			CHECK(split_container->get_split_offset() == 100);
+
+			// Change size so that the first child changes size.
+			split_container->set_size(Size2(80, 500));
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, 80 - separator_size.x, separator_size.x);
+			CHECK(split_container->get_split_offset() == 100);
+
+			// Increase size again.
+			split_container->set_size(Size2(500, 500));
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos + 100, separator_size.x);
+			CHECK(split_container->get_split_offset() == 100);
+		}
+
+		SUBCASE("[SplitContainer] First child expanded") {
+			int def_pos = split_container->get_size().x - separator_size.x;
+			child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+
+			// Increase the size.
+			split_container->set_size(Size2(600, 500));
+			def_pos = split_container->get_size().x - separator_size.x;
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Decrease the size.
+			split_container->set_size(Size2(400, 500));
+			def_pos = split_container->get_size().x - separator_size.x;
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Change size with a split offset.
+			split_container->set_split_offset(-100);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos - 100, separator_size.x);
+
+			split_container->set_size(Size2(500, 500));
+			def_pos = split_container->get_size().x - separator_size.x;
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos - 100, separator_size.x);
+			CHECK(split_container->get_split_offset() == -100);
+
+			// Change size so that the second child changes size.
+			split_container->set_size(Size2(80, 500));
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, 0, separator_size.x);
+			CHECK(split_container->get_split_offset() == -100);
+
+			// Increase size again.
+			split_container->set_size(Size2(500, 500));
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos - 100, separator_size.x);
+			CHECK(split_container->get_split_offset() == -100);
+		}
+
+		SUBCASE("[SplitContainer] Second child expanded") {
+			int def_pos = 0;
+			child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+
+			// Increase the size.
+			split_container->set_size(Size2(600, 500));
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Decrease the size.
+			split_container->set_size(Size2(400, 500));
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Change size with a split offset.
+			split_container->set_split_offset(100);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos + 100, separator_size.x);
+
+			split_container->set_size(Size2(500, 500));
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos + 100, separator_size.x);
+			CHECK(split_container->get_split_offset() == 100);
+
+			// Change size so that the first child changes size.
+			split_container->set_size(Size2(80, 500));
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, 80 - separator_size.x, separator_size.x);
+			CHECK(split_container->get_split_offset() == 100);
+
+			// Increase size again.
+			split_container->set_size(Size2(500, 500));
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos + 100, separator_size.x);
+			CHECK(split_container->get_split_offset() == 100);
+		}
+
+		SUBCASE("[SplitContainer] Both children expanded") {
+			int def_pos = (split_container->get_size().x - separator_size.x) / 2;
+			child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+
+			// Increase the size.
+			split_container->set_size(Size2(600, 500));
+			def_pos = (split_container->get_size().x - separator_size.x) / 2;
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Decrease the size.
+			split_container->set_size(Size2(400, 500));
+			def_pos = (split_container->get_size().x - separator_size.x) / 2;
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Change size with a split offset.
+			split_container->set_split_offset(100);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos + 100, separator_size.x);
+
+			split_container->set_size(Size2(500, 500));
+			def_pos = (split_container->get_size().x - separator_size.x) / 2;
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos + 100, separator_size.x);
+			CHECK(split_container->get_split_offset() == 100);
+
+			// Change size so that the second child is minimized.
+			split_container->set_size(Size2(80, 500));
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, 80 - separator_size.x, separator_size.x);
+			CHECK(split_container->get_split_offset() == 100);
+
+			// Increase size again.
+			split_container->set_size(Size2(500, 500));
+			def_pos = (split_container->get_size().x - separator_size.x) / 2;
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos + 100, separator_size.x);
+			CHECK(split_container->get_split_offset() == 100);
+		}
+
+		SUBCASE("[SplitContainer] Unequal stretch ratios") {
+			int def_pos = (split_container->get_size().x * 2 / 3) - separator_size.x / 2;
+			child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			child_a->set_stretch_ratio(2.0);
+			MessageQueue::get_singleton()->flush();
+
+			// Increase the size.
+			split_container->set_size(Size2(600, 500));
+			def_pos = (split_container->get_size().x * 2 / 3) - separator_size.x / 2;
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Decrease the size.
+			split_container->set_size(Size2(400, 500));
+			def_pos = (split_container->get_size().x * 2 / 3) - separator_size.x / 2;
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos, separator_size.x);
+
+			// Change size with a split offset.
+			split_container->set_split_offset(100);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos + 100, separator_size.x);
+
+			split_container->set_size(Size2(500, 500));
+			def_pos = (split_container->get_size().x * 2 / 3) - separator_size.x / 2;
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos + 100, separator_size.x);
+			CHECK(split_container->get_split_offset() == 100);
+
+			// Change size so that the second child is minimized.
+			split_container->set_size(Size2(80, 500));
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, 80 - separator_size.x, separator_size.x);
+			CHECK(split_container->get_split_offset() == 100);
+
+			// Increase size again.
+			split_container->set_size(Size2(500, 500));
+			def_pos = (split_container->get_size().x * 2 / 3) - separator_size.x / 2;
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, def_pos + 100, separator_size.x);
+			CHECK(split_container->get_split_offset() == 100);
+		}
+	}
+
+	SUBCASE("[SplitContainer] Drag") {
+		SUBCASE("[SplitContainer] Vertical, no expand flags") {
+			SIGNAL_WATCH(split_container, "dragged");
+			Array signal_args;
+			signal_args.push_back(Array());
+			((Array)signal_args[0]).push_back(0);
+
+			split_container->set_vertical(true);
+			Point2 mouse_offset = Point2(1, 1);
+			int dragger_pos = 0;
+			int split_dragger_ofs = 0;
+
+			// Grab the dragger.
+			SEND_GUI_MOUSE_BUTTON_EVENT(mouse_offset + Point2(0, dragger_pos), MouseButton::LEFT, MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.y, false);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+			SIGNAL_CHECK_FALSE("dragged");
+
+			// Move the dragger.
+			dragger_pos = 10;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(0, dragger_pos), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.y, false);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+			// It is clamped.
+			split_container->clamp_split_offset();
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+			((Array)signal_args[0])[0] = split_container->get_split_offset();
+			SIGNAL_CHECK("dragged", signal_args);
+
+			// Move down.
+			dragger_pos = 400;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(0, dragger_pos), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.y, false);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+			((Array)signal_args[0])[0] = split_container->get_split_offset();
+			SIGNAL_CHECK("dragged", signal_args);
+
+			// Moves even when mouse is outside.
+			dragger_pos = split_container->get_size().y - separator_size.y;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(0, 1000), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.y, false);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+			((Array)signal_args[0])[0] = split_container->get_split_offset();
+			SIGNAL_CHECK("dragged", signal_args);
+
+			// Move up.
+			dragger_pos = 100;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(0, dragger_pos), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.y, false);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+			((Array)signal_args[0])[0] = split_container->get_split_offset();
+			SIGNAL_CHECK("dragged", signal_args);
+
+			// Release.
+			SEND_GUI_MOUSE_BUTTON_RELEASED_EVENT(mouse_offset + Point2(0, dragger_pos), MouseButton::LEFT, MouseButtonMask::NONE, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.y, false);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+			SIGNAL_CHECK_FALSE("dragged");
+
+			// No longer moves with the mouse.
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(0, 200), MouseButtonMask::NONE, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.y, false);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+			SIGNAL_CHECK_FALSE("dragged");
+
+			SIGNAL_UNWATCH(split_container, "dragged");
+		}
+
+		SUBCASE("[SplitContainer] No expand flags") {
+			Point2 mouse_offset = Point2(1, 1);
+			int dragger_pos = 0;
+			int split_dragger_ofs = 0;
+
+			// Grab the dragger.
+			SEND_GUI_MOUSE_BUTTON_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButton::LEFT, MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Move the dragger.
+			dragger_pos = 10;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+			// It is clamped.
+			split_container->clamp_split_offset();
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Continue moving.
+			dragger_pos = 400;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Moves even when mouse is outside.
+			dragger_pos = split_container->get_size().x - separator_size.x;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(1000, 0), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Move back in.
+			dragger_pos = 100;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Release.
+			SEND_GUI_MOUSE_BUTTON_RELEASED_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButton::LEFT, MouseButtonMask::NONE, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// No longer moves with the mouse.
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(200, 0), MouseButtonMask::NONE, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+		}
+
+		SUBCASE("[SplitContainer] First child expanded") {
+			child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+			Point2 mouse_offset = Point2(1, 1);
+			int dragger_pos = split_container->get_size().x - separator_size.x;
+			int split_dragger_ofs = -dragger_pos;
+
+			// Grab the dragger.
+			SEND_GUI_MOUSE_BUTTON_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButton::LEFT, MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Move the dragger.
+			dragger_pos -= 10;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+			// It is clamped.
+			split_container->clamp_split_offset();
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Continue moving.
+			dragger_pos = 400;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Moves even when mouse is outside.
+			dragger_pos = split_container->get_size().x - separator_size.x;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(1000, 0), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Move back in.
+			dragger_pos = 100;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Release.
+			SEND_GUI_MOUSE_BUTTON_RELEASED_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButton::LEFT, MouseButtonMask::NONE, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// No longer moves with the mouse.
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(200, 0), MouseButtonMask::NONE, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+		}
+
+		SUBCASE("[SplitContainer] Second child expanded") {
+			child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+			Point2 mouse_offset = Point2(1, 1);
+			int dragger_pos = 0;
+			int split_dragger_ofs = 0;
+
+			// Grab the dragger.
+			SEND_GUI_MOUSE_BUTTON_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButton::LEFT, MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Move the dragger.
+			dragger_pos = 10;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+			// It is clamped.
+			split_container->clamp_split_offset();
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Continue moving.
+			dragger_pos = 400;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Moves even when mouse is outside.
+			dragger_pos = split_container->get_size().x - separator_size.x;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(1000, 0), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Move back in.
+			dragger_pos = 100;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Release.
+			SEND_GUI_MOUSE_BUTTON_RELEASED_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButton::LEFT, MouseButtonMask::NONE, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// No longer moves with the mouse.
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(200, 0), MouseButtonMask::NONE, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+		}
+
+		SUBCASE("[SplitContainer] Both children expanded") {
+			child_a->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			child_b->set_h_size_flags(Control::SIZE_EXPAND_FILL);
+			MessageQueue::get_singleton()->flush();
+			Point2 mouse_offset = Point2(1, 1);
+			int dragger_pos = (split_container->get_size().x - separator_size.x) / 2;
+			int split_dragger_ofs = -dragger_pos;
+
+			// Grab the dragger.
+			SEND_GUI_MOUSE_BUTTON_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButton::LEFT, MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Move the dragger.
+			dragger_pos += 10;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+			// It is clamped.
+			split_container->clamp_split_offset();
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Continue moving.
+			dragger_pos = 400;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Moves even when mouse is outside.
+			dragger_pos = split_container->get_size().x - separator_size.x;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(1000, 0), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Move back in.
+			dragger_pos = 100;
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButtonMask::LEFT, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// Release.
+			SEND_GUI_MOUSE_BUTTON_RELEASED_EVENT(mouse_offset + Point2(dragger_pos, 0), MouseButton::LEFT, MouseButtonMask::NONE, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+
+			// No longer moves with the mouse.
+			SEND_GUI_MOUSE_MOTION_EVENT(mouse_offset + Point2(200, 0), MouseButtonMask::NONE, Key::NONE);
+			MessageQueue::get_singleton()->flush();
+			check_position(split_container, dragger_pos, separator_size.x);
+			CHECK(split_container->get_split_offset() == dragger_pos + split_dragger_ofs);
+		}
+	}
+
+	memdelete(child_b);
+	memdelete(child_a);
+	memdelete(split_container);
+}
+
+} // namespace TestSplitContainer
+
+#endif // TEST_SPLIT_CONTAINER_H
diff --git a/tests/test_main.cpp b/tests/test_main.cpp
index 6569e8f9b11..580c3df32e3 100644
--- a/tests/test_main.cpp
+++ b/tests/test_main.cpp
@@ -149,6 +149,7 @@
 #include "tests/scene/test_color_picker.h"
 #include "tests/scene/test_graph_node.h"
 #include "tests/scene/test_option_button.h"
+#include "tests/scene/test_split_container.h"
 #include "tests/scene/test_tab_bar.h"
 #include "tests/scene/test_tab_container.h"
 #include "tests/scene/test_text_edit.h"