public function testIsEscapingHtml()
 {
     $string = new String('<h1>Lorem ipsum dolor</h1>');
     $result = $string->escapeHtml();
     $this->assertInstanceOf('Simple\\Type\\String', $result);
     $this->assertEquals('&lt;h1&gt;Lorem ipsum dolor&lt;/h1&gt;', $result->toString());
 }