Add test for global styles coming from 3rd party blocks

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

@@ -69,6 +69,11 @@
 				"filter": {
 					"duotone": "var(--wp--preset--duotone--custom-duotone)"
 				}
+			},
+			"my/third-party-block": {
+				"color": {
+					"background": "hotpink"
+				}
 			}
 		},
 		"elements": {

tests/phpunit/tests/theme/wpGetGlobalStylesForBlocks.php

@@ -0,0 +1,90 @@
+<?php
+
+/**
+ * Tests wp_add_global_styles_for_blocks().
+ *
+ * @group themes
+ */
+class Tests_Theme_wpGetGlobalStylesForBlocks extends WP_UnitTestCase {
+
+	/**
+	 * Theme root directory.
+	 *
+	 * @var string
+	 */
+	private $theme_root;
+
+	/**
+	 * Original theme directory.
+	 *
+	 * @var string
+	 */
+	private $orig_theme_dir;
+
+	public function set_up() {
+		parent::set_up();
+
+		$this->orig_theme_dir = $GLOBALS['wp_theme_directories'];
+		$this->theme_root     = realpath( DIR_TESTDATA . '/themedir1' );
+
+		// /themes is necessary as theme.php functions assume /themes is the root if there is only one root.
+		$GLOBALS['wp_theme_directories'] = array( WP_CONTENT_DIR . '/themes', $this->theme_root );
+
+		// Set up the new root.
+		add_filter( 'theme_root', array( $this, 'filter_set_theme_root' ) );
+		add_filter( 'stylesheet_root', array( $this, 'filter_set_theme_root' ) );
+		add_filter( 'template_root', array( $this, 'filter_set_theme_root' ) );
+
+		// Clear caches.
+		wp_clean_themes_cache();
+		unset( $GLOBALS['wp_themes'] );
+	}
+
+	public function tear_down() {
+		$GLOBALS['wp_theme_directories'] = $this->orig_theme_dir;
+
+		// Clear up the filters to modify the theme root.
+		remove_filter( 'theme_root', array( $this, 'filter_set_theme_root' ) );
+		remove_filter( 'stylesheet_root', array( $this, 'filter_set_theme_root' ) );
+		remove_filter( 'template_root', array( $this, 'filter_set_theme_root' ) );
+
+		wp_clean_themes_cache();
+		unset( $GLOBALS['wp_themes'] );
+
+		parent::tear_down();
+	}
+
+	/**
+	 * Cleans up global scope.
+	 *
+	 * @global WP_Styles $wp_styles
+	 */
+	public function clean_up_global_scope() {
+		global $wp_styles;
+		parent::clean_up_global_scope();
+		$wp_styles = null;
+	}
+
+	public function filter_set_theme_root() {
+		return $this->theme_root;
+	}
+
+	public function test_styles_for_blocks() {
+		switch_theme( 'block-theme' );
+
+		$name     = 'my/third-party-block';
+		$settings = array(
+			'icon'            => 'text',
+			'category'        => 'common',
+			'render_callback' => 'foo',
+		);
+		register_block_type( $name, $settings );
+		wp_enqueue_global_styles();
+		unregister_block_type( $name );
+
+		$this->assertStringContainsString( '.wp-block-my-third-party-block{background-color: hotpink;}', get_echo( 'wp_print_styles' ), '3rd party block styles are included' );
+
+		switch_theme( WP_DEFAULT_THEME );
+	}
+
+}