remove font files created by tests after tests run (#54771)

phpunit/tests/fonts/font-library/wpRestFontLibraryController/base.php

@@ -7,9 +7,19 @@
  */
 abstract class WP_REST_Font_Library_Controller_UnitTestCase extends WP_UnitTestCase {
 
+	/**
+	 * Fonts directory.
+	 *
+	 * @var string
+	 */
+	protected static $fonts_dir;
+
+
 	public function set_up() {
 		parent::set_up();
 
+		static::$fonts_dir = WP_Font_Library::get_fonts_dir();
+
 		// Create a user with administrator role.
 		$admin_id = $this->factory->user->create(
 			array(
@@ -30,5 +40,10 @@ public function tear_down() {
 		$property   = $reflection->getProperty( 'collections' );
 		$property->setAccessible( true );
 		$property->setValue( array() );
+
+		// Clean up the /fonts directory.
+		foreach ( $this->files_in_dir( static::$fonts_dir ) as $file ) {
+			@unlink( $file );
+		}
 	}
 }