Fix TabBar initialization issue and add tests

1 files changed, 864 insertions, 0 deletions

diff --git a/tests/scene/test_tab_bar.h b/tests/scene/test_tab_bar.h
new file mode 100644
index 0000000000..147513bb69
--- /dev/null
+++ b/tests/scene/test_tab_bar.h
@@ -0,0 +1,864 @@
+/**************************************************************************/
+/*  test_tab_bar.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_TAB_BAR_H
+#define TEST_TAB_BAR_H
+
+#include "scene/gui/tab_bar.h"
+#include "scene/main/window.h"
+
+#include "tests/test_macros.h"
+
+namespace TestTabBar {
+static inline Array build_array() {
+	return Array();
+}
+template <typename... Targs>
+static inline Array build_array(Variant item, Targs... Fargs) {
+	Array a = build_array(Fargs...);
+	a.push_front(item);
+	return a;
+}
+
+TEST_CASE("[SceneTree][TabBar] tab operations") {
+	TabBar *tab_bar = memnew(TabBar);
+	SceneTree::get_singleton()->get_root()->add_child(tab_bar);
+	tab_bar->set_clip_tabs(false);
+	MessageQueue::get_singleton()->flush();
+
+	SIGNAL_WATCH(tab_bar, "tab_selected");
+	SIGNAL_WATCH(tab_bar, "tab_changed");
+
+	SUBCASE("[TabBar] no tabs") {
+		CHECK(tab_bar->get_tab_count() == 0);
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == -1);
+	}
+
+	SUBCASE("[TabBar] add tabs") {
+		tab_bar->add_tab("tab0");
+		CHECK(tab_bar->get_tab_count() == 1);
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK("tab_selected", build_array(build_array(0)));
+		SIGNAL_CHECK("tab_changed", build_array(build_array(0)));
+
+		tab_bar->add_tab("tab1");
+		CHECK(tab_bar->get_tab_count() == 2);
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		tab_bar->add_tab("tab2");
+		CHECK(tab_bar->get_tab_count() == 3);
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		CHECK(tab_bar->get_tab_title(0) == "tab0");
+		CHECK(tab_bar->get_tab_tooltip(0) == "");
+		CHECK(tab_bar->get_tab_text_direction(0) == Control::TEXT_DIRECTION_INHERITED);
+		CHECK_FALSE(tab_bar->is_tab_disabled(0));
+		CHECK_FALSE(tab_bar->is_tab_hidden(0));
+
+		CHECK(tab_bar->get_tab_title(1) == "tab1");
+		CHECK(tab_bar->get_tab_tooltip(1) == "");
+		CHECK(tab_bar->get_tab_text_direction(1) == Control::TEXT_DIRECTION_INHERITED);
+		CHECK_FALSE(tab_bar->is_tab_disabled(1));
+		CHECK_FALSE(tab_bar->is_tab_hidden(1));
+
+		CHECK(tab_bar->get_tab_title(2) == "tab2");
+		CHECK(tab_bar->get_tab_tooltip(2) == "");
+		CHECK(tab_bar->get_tab_text_direction(2) == Control::TEXT_DIRECTION_INHERITED);
+		CHECK_FALSE(tab_bar->is_tab_disabled(2));
+		CHECK_FALSE(tab_bar->is_tab_hidden(2));
+	}
+
+	SUBCASE("[TabBar] set tab count") {
+		// Adds multiple tabs at once.
+		tab_bar->set_tab_count(3);
+		CHECK(tab_bar->get_tab_count() == 3);
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		CHECK(tab_bar->get_tab_title(0) == "");
+		CHECK(tab_bar->get_tab_tooltip(0) == "");
+		CHECK(tab_bar->get_tab_text_direction(0) == Control::TEXT_DIRECTION_INHERITED);
+		CHECK_FALSE(tab_bar->is_tab_disabled(0));
+		CHECK_FALSE(tab_bar->is_tab_hidden(0));
+
+		CHECK(tab_bar->get_tab_title(1) == "");
+		CHECK(tab_bar->get_tab_tooltip(1) == "");
+		CHECK(tab_bar->get_tab_text_direction(1) == Control::TEXT_DIRECTION_INHERITED);
+		CHECK_FALSE(tab_bar->is_tab_disabled(1));
+		CHECK_FALSE(tab_bar->is_tab_hidden(1));
+
+		CHECK(tab_bar->get_tab_title(2) == "");
+		CHECK(tab_bar->get_tab_tooltip(2) == "");
+		CHECK(tab_bar->get_tab_text_direction(2) == Control::TEXT_DIRECTION_INHERITED);
+		CHECK_FALSE(tab_bar->is_tab_disabled(2));
+		CHECK_FALSE(tab_bar->is_tab_hidden(2));
+
+		// Setting to less tabs than there are removes from the end.
+		tab_bar->set_tab_title(0, "tab0");
+		tab_bar->set_tab_title(1, "tab1");
+		tab_bar->set_tab_title(2, "tab2");
+
+		tab_bar->set_tab_count(2);
+		CHECK(tab_bar->get_tab_count() == 2);
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		CHECK(tab_bar->get_tab_title(0) == "tab0");
+		CHECK(tab_bar->get_tab_title(1) == "tab1");
+
+		// Remove all tabs.
+		tab_bar->set_tab_count(0);
+		CHECK(tab_bar->get_tab_count() == 0);
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == -1);
+	}
+
+	SUBCASE("[TabBar] clear tabs") {
+		CHECK(tab_bar->get_tab_count() == 0);
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == -1);
+
+		tab_bar->set_tab_count(2);
+		CHECK(tab_bar->get_tab_count() == 2);
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+
+		tab_bar->clear_tabs();
+		CHECK(tab_bar->get_tab_count() == 0);
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+	}
+
+	SUBCASE("[TabBar] remove tabs") {
+		tab_bar->add_tab("tab0");
+		tab_bar->add_tab("tab1");
+		tab_bar->add_tab("tab2");
+		tab_bar->set_current_tab(1);
+		CHECK(tab_bar->get_tab_count() == 3);
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+
+		// Remove first tab.
+		tab_bar->remove_tab(0);
+		CHECK(tab_bar->get_tab_count() == 2);
+		CHECK(tab_bar->get_tab_title(0) == "tab1");
+		CHECK(tab_bar->get_tab_title(1) == "tab2");
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// Remove last tab.
+		tab_bar->remove_tab(1);
+		CHECK(tab_bar->get_tab_count() == 1);
+		CHECK(tab_bar->get_tab_title(0) == "tab1");
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// Remove only tab.
+		tab_bar->remove_tab(0);
+		CHECK(tab_bar->get_tab_count() == 0);
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK("tab_changed", build_array(build_array(-1)));
+
+		// Remove current tab when there are other tabs.
+		tab_bar->add_tab("tab0");
+		tab_bar->add_tab("tab1");
+		tab_bar->add_tab("tab2");
+		tab_bar->set_current_tab(1);
+		tab_bar->set_current_tab(2);
+		CHECK(tab_bar->get_tab_count() == 3);
+		CHECK(tab_bar->get_current_tab() == 2);
+		CHECK(tab_bar->get_previous_tab() == 1);
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+
+		tab_bar->remove_tab(2);
+		CHECK(tab_bar->get_tab_count() == 2);
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK("tab_changed", build_array(build_array(1)));
+	}
+
+	SUBCASE("[TabBar] move tabs") {
+		tab_bar->add_tab("tab0");
+		tab_bar->add_tab("tab1");
+		tab_bar->add_tab("tab2");
+		tab_bar->set_current_tab(1);
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+
+		// Don't move if index is the same.
+		tab_bar->move_tab(0, 0);
+		CHECK(tab_bar->get_tab_title(0) == "tab0");
+		CHECK(tab_bar->get_tab_title(1) == "tab1");
+		CHECK(tab_bar->get_tab_title(2) == "tab2");
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// Move the first tab to the end.
+		tab_bar->move_tab(0, 2);
+		CHECK(tab_bar->get_tab_title(0) == "tab1");
+		CHECK(tab_bar->get_tab_title(1) == "tab2");
+		CHECK(tab_bar->get_tab_title(2) == "tab0");
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == 2);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// Move the second tab to the front.
+		tab_bar->move_tab(1, 0);
+		CHECK(tab_bar->get_tab_title(0) == "tab2");
+		CHECK(tab_bar->get_tab_title(1) == "tab1");
+		CHECK(tab_bar->get_tab_title(2) == "tab0");
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 2);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+	}
+
+	SUBCASE("[TabBar] set current tab") {
+		tab_bar->add_tab("tab0");
+		tab_bar->add_tab("tab1");
+		tab_bar->add_tab("tab2");
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK("tab_selected", build_array(build_array(0)));
+		SIGNAL_CHECK("tab_changed", build_array(build_array(0)));
+
+		// Set the current tab.
+		tab_bar->set_current_tab(1);
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_CHECK("tab_selected", build_array(build_array(1)));
+		SIGNAL_CHECK("tab_changed", build_array(build_array(1)));
+
+		// Set to same tab.
+		tab_bar->set_current_tab(1);
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 1);
+		SIGNAL_CHECK("tab_selected", build_array(build_array(1)));
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// Out of bounds.
+		ERR_PRINT_OFF;
+		tab_bar->set_current_tab(-5);
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		tab_bar->set_current_tab(5);
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+		ERR_PRINT_ON;
+	}
+
+	SUBCASE("[TabBar] deselection enabled") {
+		tab_bar->add_tab("tab0");
+		tab_bar->add_tab("tab1");
+		tab_bar->add_tab("tab2");
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+
+		// Setting deselect enabled doesn't change current tab.
+		tab_bar->set_deselect_enabled(true);
+		CHECK(tab_bar->get_deselect_enabled());
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// Can deselect all tabs by setting current to -1.
+		tab_bar->set_current_tab(-1);
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_CHECK("tab_selected", build_array(build_array(-1)));
+		SIGNAL_CHECK("tab_changed", build_array(build_array(-1)));
+
+		// Adding a tab will still set the current tab to 0.
+		tab_bar->clear_tabs();
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == -1);
+
+		tab_bar->add_tab("tab0");
+		tab_bar->add_tab("tab1");
+		tab_bar->add_tab("tab2");
+		CHECK(tab_bar->get_tab_count() == 3);
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK("tab_selected", build_array(build_array(0)));
+		SIGNAL_CHECK("tab_changed", build_array(build_array(0)));
+
+		tab_bar->set_current_tab(-1);
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+
+		// Disabling while at -1 will select the first available tab.
+		tab_bar->set_deselect_enabled(false);
+		CHECK_FALSE(tab_bar->get_deselect_enabled());
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK("tab_selected", build_array(build_array(0)));
+		SIGNAL_CHECK("tab_changed", build_array(build_array(0)));
+
+		// Cannot set to -1 if disabled.
+		ERR_PRINT_OFF;
+		tab_bar->set_current_tab(-1);
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+		ERR_PRINT_ON;
+
+		// Disabling while at -1 skips any disabled or hidden tabs.
+		tab_bar->set_deselect_enabled(true);
+		tab_bar->set_tab_disabled(0, true);
+		tab_bar->set_tab_hidden(1, true);
+		tab_bar->set_current_tab(-1);
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+		tab_bar->set_deselect_enabled(false);
+		CHECK(tab_bar->get_current_tab() == 2);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK("tab_selected", build_array(build_array(2)));
+		SIGNAL_CHECK("tab_changed", build_array(build_array(2)));
+	}
+
+	SUBCASE("[TabBar] hidden tabs") {
+		tab_bar->add_tab("tab0");
+		tab_bar->add_tab("tab1");
+		tab_bar->add_tab("tab2");
+		tab_bar->set_current_tab(1);
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		CHECK_FALSE(tab_bar->is_tab_hidden(1));
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+
+		MessageQueue::get_singleton()->flush();
+		Vector<Rect2> tab_rects = {
+			tab_bar->get_tab_rect(0),
+			tab_bar->get_tab_rect(1),
+			tab_bar->get_tab_rect(2)
+		};
+
+		// Hiding a tab does not affect current tab.
+		tab_bar->set_tab_hidden(1, true);
+		CHECK(tab_bar->is_tab_hidden(1));
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// The tabs after are moved over.
+		MessageQueue::get_singleton()->flush();
+		CHECK(tab_bar->get_tab_rect(0) == tab_rects[0]);
+		CHECK(tab_bar->get_tab_rect(2) == tab_rects[1]);
+
+		// Unhiding a tab does not affect current tab.
+		tab_bar->set_tab_hidden(1, false);
+		CHECK_FALSE(tab_bar->is_tab_hidden(1));
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// The tabs are back where they were.
+		MessageQueue::get_singleton()->flush();
+		CHECK(tab_bar->get_tab_rect(0) == tab_rects[0]);
+		CHECK(tab_bar->get_tab_rect(1) == tab_rects[1]);
+		CHECK(tab_bar->get_tab_rect(2) == tab_rects[2]);
+	}
+
+	SUBCASE("[TabBar] disabled tabs") {
+		tab_bar->add_tab("tab0");
+		tab_bar->add_tab("tab1");
+		tab_bar->add_tab("tab2");
+		CHECK_FALSE(tab_bar->is_tab_disabled(1));
+		tab_bar->set_current_tab(1);
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		CHECK_FALSE(tab_bar->is_tab_hidden(1));
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+
+		// Disabling a tab does not affect current tab.
+		tab_bar->set_tab_disabled(1, true);
+		CHECK(tab_bar->is_tab_disabled(1));
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// Enabling a tab does not affect current tab.
+		tab_bar->set_tab_disabled(1, false);
+		CHECK_FALSE(tab_bar->is_tab_disabled(1));
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+	}
+
+	SUBCASE("[TabBar] select next available") {
+		tab_bar->add_tab("tab0");
+		tab_bar->add_tab("tab1");
+		tab_bar->add_tab("tab2");
+		tab_bar->add_tab("tab3");
+		tab_bar->add_tab("tab4");
+		tab_bar->set_tab_disabled(2, true);
+		tab_bar->set_tab_hidden(3, true);
+		tab_bar->set_current_tab(0);
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+
+		// Selects the next tab.
+		CHECK(tab_bar->select_next_available());
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_CHECK("tab_selected", build_array(build_array(1)));
+		SIGNAL_CHECK("tab_changed", build_array(build_array(1)));
+
+		// Skips over disabled and hidden tabs.
+		CHECK(tab_bar->select_next_available());
+		CHECK(tab_bar->get_current_tab() == 4);
+		CHECK(tab_bar->get_previous_tab() == 1);
+		SIGNAL_CHECK("tab_selected", build_array(build_array(4)));
+		SIGNAL_CHECK("tab_changed", build_array(build_array(4)));
+
+		// Does not wrap around.
+		CHECK_FALSE(tab_bar->select_next_available());
+		CHECK(tab_bar->get_current_tab() == 4);
+		CHECK(tab_bar->get_previous_tab() == 1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// Fails if there is only one valid tab.
+		tab_bar->remove_tab(0);
+		tab_bar->remove_tab(3);
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+
+		CHECK_FALSE(tab_bar->select_next_available());
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// Fails if there are no valid tabs.
+		tab_bar->remove_tab(0);
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+
+		CHECK_FALSE(tab_bar->select_next_available());
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// Fails if there are no tabs.
+		tab_bar->clear_tabs();
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+
+		CHECK_FALSE(tab_bar->select_next_available());
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+	}
+
+	SUBCASE("[TabBar] select previous available") {
+		tab_bar->add_tab("tab0");
+		tab_bar->add_tab("tab1");
+		tab_bar->add_tab("tab2");
+		tab_bar->add_tab("tab3");
+		tab_bar->add_tab("tab4");
+		tab_bar->set_tab_disabled(1, true);
+		tab_bar->set_tab_hidden(2, true);
+		tab_bar->set_current_tab(4);
+		CHECK(tab_bar->get_current_tab() == 4);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+
+		// Selects the previous tab.
+		CHECK(tab_bar->select_previous_available());
+		CHECK(tab_bar->get_current_tab() == 3);
+		CHECK(tab_bar->get_previous_tab() == 4);
+		SIGNAL_CHECK("tab_selected", build_array(build_array(3)));
+		SIGNAL_CHECK("tab_changed", build_array(build_array(3)));
+
+		// Skips over disabled and hidden tabs.
+		CHECK(tab_bar->select_previous_available());
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == 3);
+		SIGNAL_CHECK("tab_selected", build_array(build_array(0)));
+		SIGNAL_CHECK("tab_changed", build_array(build_array(0)));
+
+		// Does not wrap around.
+		CHECK_FALSE(tab_bar->select_previous_available());
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == 3);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// Fails if there is only one valid tab.
+		tab_bar->remove_tab(4);
+		tab_bar->remove_tab(3);
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == 2);
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+
+		CHECK_FALSE(tab_bar->select_previous_available());
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == 2);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// Fails if there are no valid tabs.
+		tab_bar->remove_tab(0);
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == 1);
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+
+		CHECK_FALSE(tab_bar->select_previous_available());
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == 1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// Fails if there are no tabs.
+		tab_bar->clear_tabs();
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_DISCARD("tab_selected");
+		SIGNAL_DISCARD("tab_changed");
+
+		CHECK_FALSE(tab_bar->select_previous_available());
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+	}
+
+	SIGNAL_UNWATCH(tab_bar, "tab_selected");
+	SIGNAL_UNWATCH(tab_bar, "tab_changed");
+
+	memdelete(tab_bar);
+}
+
+TEST_CASE("[SceneTree][TabBar] initialization") {
+	TabBar *tab_bar = memnew(TabBar);
+
+	SIGNAL_WATCH(tab_bar, "tab_selected");
+	SIGNAL_WATCH(tab_bar, "tab_changed");
+
+	SUBCASE("[TabBar] current tab can be set before tabs are set") {
+		// This queues the current tab to update on when tabs are set.
+		tab_bar->set_current_tab(1);
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		tab_bar->set_tab_count(2);
+		CHECK(tab_bar->get_tab_count() == 2);
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_CHECK("tab_selected", build_array(build_array(1)));
+		SIGNAL_CHECK("tab_changed", build_array(build_array(1)));
+
+		// Does not work again.
+		ERR_PRINT_OFF;
+		tab_bar->set_current_tab(2);
+		CHECK(tab_bar->get_tab_count() == 2);
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		tab_bar->set_tab_count(3);
+		CHECK(tab_bar->get_tab_count() == 3);
+		CHECK(tab_bar->get_current_tab() == 1);
+		CHECK(tab_bar->get_previous_tab() == 0);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+		ERR_PRINT_ON;
+	}
+
+	SUBCASE("[TabBar] setting tabs works normally if no current tab was set") {
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == -1);
+
+		tab_bar->set_tab_count(2);
+		CHECK(tab_bar->get_tab_count() == 2);
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+	}
+
+	SUBCASE("[TabBar] cannot set current tab to an invalid value before tabs are set") {
+		tab_bar->set_current_tab(100);
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// This will print an error message as if `set_current_tab` was called after.
+		ERR_PRINT_OFF;
+		tab_bar->set_tab_count(2);
+		CHECK(tab_bar->get_tab_count() == 2);
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+		ERR_PRINT_ON;
+	}
+
+	SUBCASE("[TabBar] setting the current tab before tabs only works when out of tree") {
+		tab_bar->set_current_tab(1);
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		SceneTree::get_singleton()->get_root()->add_child(tab_bar);
+		MessageQueue::get_singleton()->flush();
+		CHECK(tab_bar->get_tab_count() == 0);
+		CHECK(tab_bar->get_current_tab() == -1);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+
+		// Works normally.
+		tab_bar->set_tab_count(2);
+		CHECK(tab_bar->get_tab_count() == 2);
+		CHECK(tab_bar->get_current_tab() == 0);
+		CHECK(tab_bar->get_previous_tab() == -1);
+		SIGNAL_CHECK_FALSE("tab_selected");
+		SIGNAL_CHECK_FALSE("tab_changed");
+	}
+
+	SIGNAL_UNWATCH(tab_bar, "tab_selected");
+	SIGNAL_UNWATCH(tab_bar, "tab_changed");
+
+	memdelete(tab_bar);
+}
+
+TEST_CASE("[SceneTree][TabBar] layout and offset") {
+	TabBar *tab_bar = memnew(TabBar);
+	SceneTree::get_singleton()->get_root()->add_child(tab_bar);
+
+	tab_bar->set_clip_tabs(false);
+	tab_bar->add_tab("tab0");
+	tab_bar->add_tab("tab1 ");
+	tab_bar->add_tab("tab2    ");
+	MessageQueue::get_singleton()->flush();
+	Size2 all_tabs_size = tab_bar->get_size();
+
+	Vector<Rect2> tab_rects = {
+		tab_bar->get_tab_rect(0),
+		tab_bar->get_tab_rect(1),
+		tab_bar->get_tab_rect(2)
+	};
+
+	SUBCASE("[TabBar] tabs are arranged next to each other") {
+		// Horizontal positions are next to each other.
+		CHECK(tab_rects[0].position.x == 0);
+		CHECK(tab_rects[1].position.x == tab_rects[0].size.x);
+		CHECK(tab_rects[2].position.x == tab_rects[1].position.x + tab_rects[1].size.x);
+
+		// Fills the entire width.
+		CHECK(tab_rects[2].position.x + tab_rects[2].size.x == all_tabs_size.x);
+
+		// Horizontal sizes are positive.
+		CHECK(tab_rects[0].size.x > 0);
+		CHECK(tab_rects[1].size.x > 0);
+		CHECK(tab_rects[2].size.x > 0);
+
+		// Vertical positions are at 0.
+		CHECK(tab_rects[0].position.y == 0);
+		CHECK(tab_rects[1].position.y == 0);
+		CHECK(tab_rects[2].position.y == 0);
+
+		// Vertical sizes are the same.
+		CHECK(tab_rects[0].size.y == tab_rects[1].size.y);
+		CHECK(tab_rects[1].size.y == tab_rects[2].size.y);
+	}
+
+	SUBCASE("[TabBar] tab alignment") {
+		// Add extra space so the alignment can be seen.
+		tab_bar->set_size(Size2(all_tabs_size.x + 100, all_tabs_size.y));
+
+		// Left alignment.
+		tab_bar->set_tab_alignment(TabBar::ALIGNMENT_LEFT);
+		MessageQueue::get_singleton()->flush();
+		tab_rects = {
+			tab_bar->get_tab_rect(0),
+			tab_bar->get_tab_rect(1),
+			tab_bar->get_tab_rect(2)
+		};
+		CHECK(tab_bar->get_tab_alignment() == TabBar::ALIGNMENT_LEFT);
+		CHECK(tab_rects[0].position.x == 0);
+		CHECK(tab_rects[1].position.x == tab_rects[0].size.x);
+		CHECK(tab_rects[2].position.x == tab_rects[1].position.x + tab_rects[1].size.x);
+
+		// Right alignment.
+		tab_bar->set_tab_alignment(TabBar::ALIGNMENT_RIGHT);
+		MessageQueue::get_singleton()->flush();
+		tab_rects = {
+			tab_bar->get_tab_rect(0),
+			tab_bar->get_tab_rect(1),
+			tab_bar->get_tab_rect(2)
+		};
+		CHECK(tab_bar->get_tab_alignment() == TabBar::ALIGNMENT_RIGHT);
+		CHECK(tab_rects[2].position.x == tab_bar->get_size().x - tab_rects[2].size.x);
+		CHECK(tab_rects[1].position.x == tab_rects[2].position.x - tab_rects[1].size.x);
+		CHECK(tab_rects[0].position.x == tab_rects[1].position.x - tab_rects[0].size.x);
+
+		// Center alignment.
+		tab_bar->set_tab_alignment(TabBar::ALIGNMENT_CENTER);
+		MessageQueue::get_singleton()->flush();
+		tab_rects = {
+			tab_bar->get_tab_rect(0),
+			tab_bar->get_tab_rect(1),
+			tab_bar->get_tab_rect(2)
+		};
+		CHECK(tab_bar->get_tab_alignment() == TabBar::ALIGNMENT_CENTER);
+		float center_pos = tab_bar->get_size().x / 2;
+		CHECK(tab_rects[0].position.x == center_pos - all_tabs_size.x / 2);
+		CHECK(tab_rects[1].position.x == tab_rects[0].position.x + tab_rects[0].size.x);
+		CHECK(tab_rects[2].position.x == tab_rects[1].position.x + tab_rects[1].size.x);
+	}
+
+	SUBCASE("[TabBar] clip tabs") {
+		// Clip tabs disabled means all tabs are visible and the minimum size holds all of them.
+		tab_bar->set_clip_tabs(false);
+		CHECK_FALSE(tab_bar->get_clip_tabs());
+		MessageQueue::get_singleton()->flush();
+		CHECK(tab_bar->get_tab_offset() == 0);
+		CHECK(tab_bar->get_minimum_size() == tab_bar->get_size());
+		CHECK(tab_bar->get_size().x == tab_rects[0].size.x + tab_rects[1].size.x + tab_rects[2].size.x);
+		CHECK(tab_bar->get_size().y == MAX(tab_rects[0].size.y, MAX(tab_rects[1].size.y, tab_rects[2].size.y)));
+
+		tab_bar->set_clip_tabs(true);
+		CHECK(tab_bar->get_clip_tabs());
+		MessageQueue::get_singleton()->flush();
+		CHECK(tab_bar->get_tab_offset() == 0);
+
+		// Horizontal size and minimum size get set to 0.
+		CHECK(tab_bar->get_minimum_size().x == 0);
+		CHECK(tab_bar->get_minimum_size().y == all_tabs_size.y);
+		CHECK(tab_bar->get_size().x == 0);
+		CHECK(tab_bar->get_size().y == all_tabs_size.y);
+	}
+
+	SUBCASE("[TabBar] ensure tab visible") {
+		tab_bar->set_scroll_to_selected(false);
+		tab_bar->set_clip_tabs(true);
+
+		// Resize tab bar to only be able to fit 2 tabs.
+		const float offset_button_size = tab_bar->get_theme_icon("decrement_icon")->get_width() + tab_bar->get_theme_icon("increment_icon")->get_width();
+		tab_bar->set_size(Size2(tab_rects[2].size.x + tab_rects[1].size.x + offset_button_size, all_tabs_size.y));
+		MessageQueue::get_singleton()->flush();
+		CHECK(tab_bar->get_tab_offset() == 0);
+		CHECK(tab_bar->get_offset_buttons_visible());
+
+		// Scroll right to a tab that is not visible.
+		tab_bar->ensure_tab_visible(2);
+		CHECK(tab_bar->get_tab_offset() == 1);
+		CHECK(tab_bar->get_tab_rect(1).position.x == 0);
+		CHECK(tab_bar->get_tab_rect(2).position.x == tab_rects[1].size.x);
+
+		tab_bar->set_tab_offset(2);
+		CHECK(tab_bar->get_tab_offset() == 2);
+		CHECK(tab_bar->get_tab_rect(2).position.x == 0);
+
+		// Scroll left to a previous tab.
+		tab_bar->ensure_tab_visible(1);
+		CHECK(tab_bar->get_tab_offset() == 1);
+		CHECK(tab_bar->get_tab_rect(1).position.x == 0);
+		CHECK(tab_bar->get_tab_rect(2).position.x == tab_rects[1].size.x);
+
+		// Will not scroll if the tab is already visible.
+		tab_bar->ensure_tab_visible(2);
+		CHECK(tab_bar->get_tab_offset() == 1);
+		CHECK(tab_bar->get_tab_rect(1).position.x == 0);
+		CHECK(tab_bar->get_tab_rect(2).position.x == tab_rects[1].size.x);
+	}
+
+	memdelete(tab_bar);
+}
+
+// FIXME: Add tests for mouse click, keyboard navigation, and drag and drop.
+
+} // namespace TestTabBar
+
+#endif // TEST_TAB_BAR_H