Making test working again (reverting the last change)

tests/src/Util/StringsTest.php

@@ -78,7 +78,7 @@ class StringsTest extends TestCase
 
 		$this->assertEquals('[submit type="button" onclick="alert(\'failed!\');" /]', $validstring);
 		$this->assertEquals(
-			'<submit type="button" onclick="alert('failed!');" />',
+			"<submit type="button" onclick="alert('failed!');" />",
 			$escapedString
 		);
 	}