Tests: Improve theme test isolation

tests/phpunit/data/themedir1/block-theme/theme.json

@@ -96,6 +96,11 @@
 						}
 					}
 				}
+			},
+			"my/unregistered-third-party-block": {
+				"color": {
+					"background": "hotpink"
+				}
 			}
 		},
 		"elements": {

tests/phpunit/tests/template.php

@@ -151,6 +151,11 @@ public function tear_down() {
 			$registry->unregister( 'third-party/test' );
 		}
 
+		if ( isset( $GLOBALS['_wp_tests_development_mode'] ) ) {
+			remove_all_filters( 'theme_file_path' );
+			wp_theme_has_theme_json();
+		}
+
 		unset( $GLOBALS['_wp_tests_development_mode'] );
 		parent::tear_down();
 	}

tests/phpunit/tests/theme.php

@@ -33,14 +33,22 @@
 	 */
 	private $orig_theme_dir;
 
+	/**
+	 * Theme features registered before the test ran.
+	 *
+	 * @var array
+	 */
+	private $orig_theme_features;
+
 	public function set_up() {
 		global $wp_theme_directories;
 
 		parent::set_up();
 
 		// Sets up the `wp-content/themes/` directory to ensure consistency when running tests.
-		$this->orig_theme_dir = $wp_theme_directories;
-		$wp_theme_directories = array( WP_CONTENT_DIR . '/themes', realpath( DIR_TESTDATA . '/themedir1' ) );
+		$this->orig_theme_dir      = $wp_theme_directories;
+		$wp_theme_directories      = array( WP_CONTENT_DIR . '/themes', realpath( DIR_TESTDATA . '/themedir1' ) );
+		$this->orig_theme_features = $GLOBALS['_wp_theme_features'];
 
 		add_filter( 'extra_theme_headers', array( $this, 'theme_data_extra_headers' ) );
 		wp_clean_themes_cache();
@@ -56,7 +64,12 @@
 		wp_clean_themes_cache();
 		unset( $GLOBALS['wp_themes'] );
 
-		parent::tear_down();
+		try {
+			parent::tear_down();
+		} finally {
+			// Restore after the parent removes HTML5 theme support.
+			$GLOBALS['_wp_theme_features'] = $this->orig_theme_features;
+		}
 	}
 
 	public function test_wp_get_themes_default() {
@@ -428,7 +441,7 @@
 	 * @expectedDeprecated get_themes
 	 * @expectedDeprecated get_current_theme
 	 */
 	public function test_switch_theme() {
 		$themes = get_themes();
 
 		$this->assertNotEmpty( $themes );

tests/phpunit/tests/theme/support.php

@@ -5,6 +5,40 @@
  */
 class Tests_Theme_Support extends WP_UnitTestCase {
 
+	/**
+	 * Theme features registered before the test ran.
+	 *
+	 * @var array
+	 */
+	private $orig_theme_features;
+
+	/**
+	 * Nav menu locations registered before the test ran.
+	 *
+	 * @var array
+	 */
+	private $orig_registered_nav_menus;
+
+	public function set_up() {
+		parent::set_up();
+
+		$this->orig_theme_features       = $GLOBALS['_wp_theme_features'];
+		$this->orig_registered_nav_menus = $GLOBALS['_wp_registered_nav_menus'] ?? array();
+
+		// Start without support from the bootstrapped theme.
+		$GLOBALS['_wp_theme_features'] = array();
+	}
+
+	public function tear_down() {
+		try {
+			parent::tear_down();
+		} finally {
+			// Restore after the parent removes HTML5 theme support.
+			$GLOBALS['_wp_theme_features']       = $this->orig_theme_features;
+			$GLOBALS['_wp_registered_nav_menus'] = $this->orig_registered_nav_menus;
+		}
+	}
+
 	public function test_the_basics() {
 		add_theme_support( 'automatic-feed-links' );
 		$this->assertTrue( current_theme_supports( 'automatic-feed-links' ) );

tests/phpunit/tests/theme/wpAddGlobalStylesForBlocks.php

@@ -18,6 +18,13 @@ class Tests_Theme_WpAddGlobalStylesForBlocks extends WP_Theme_UnitTestCase {
 	 */
 	private $test_blocks = array();
 
+	/**
+	 * Original stylesheet.
+	 *
+	 * @var string
+	 */
+	private $original_stylesheet;
+
 	/**
 	 * Administrator ID.
 	 *
@@ -37,6 +44,7 @@ public static function set_up_before_class() {
 
 	public function set_up() {
 		parent::set_up();
+		$this->original_stylesheet = get_stylesheet();
 		remove_action( 'wp_print_styles', 'print_emoji_styles' );
 	}
 
@@ -49,6 +57,10 @@ public function tear_down() {
 			$this->test_blocks = array();
 		}
 
+		if ( get_stylesheet() !== $this->original_stylesheet ) {
+			switch_theme( $this->original_stylesheet );
+		}
+
 		parent::tear_down();
 	}
 
@@ -63,7 +75,7 @@ public function test_third_party_blocks_inline_styles_not_register_to_global_sty
 		wp_add_global_styles_for_blocks();
 
 		$this->assertNotContains(
-			':root :where(.wp-block-my-third-party-block){background-color: hotpink;}',
+			':root :where(.wp-block-my-unregistered-third-party-block){background-color: hotpink;}',
 			$this->get_global_styles()
 		);
 	}