Add tests for title elements

Author: PolariTOON

test/html/title-element.js

@@ -0,0 +1,39 @@
+const assert = require('../assert.js').for('HTMLTitleElement');
+
+const {DOMParser, parseHTML} = global[Symbol.for('linkedom')];
+
+const {document: htmlDoc} = parseHTML('<title>abc&<>"\t\n\r\xA0</title>');
+assert(
+  htmlDoc.toString(),
+  '<title>abc&amp;&lt;&gt;"\t\n\r&nbsp;</title>'
+);
+
+const htmlTitle = htmlDoc.querySelector('title');
+htmlTitle.innerHTML = '<a>sub element</a>';
+assert(
+  htmlTitle.innerHTML,
+  '&lt;a&gt;sub element&lt;/a&gt;'
+);
+assert(
+  htmlDoc.toString(),
+  '<title>&lt;a&gt;sub element&lt;/a&gt;</title>'
+);
+assert(htmlDoc.querySelectorAll('a').length, 0);
+
+const xhtmlDoc = (new DOMParser).parseFromString('<title xmlns="http://www.w3.org/1999/xhtml">abc&<>"\t\n\r\xA0</title>', 'application/xhtml+xml');
+assert(
+  xhtmlDoc.toString(),
+  '<?xml version="1.0" encoding="utf-8"?><title xmlns="http://www.w3.org/1999/xhtml">abc&amp;&lt;&gt;"\t\n\r\xA0</title>'
+);
+
+const xhtmlTitle = xhtmlDoc.querySelector('title');
+xhtmlTitle.innerHTML = '<a>sub element</a>';
+assert(
+  xhtmlTitle.innerHTML,
+  '<a>sub element</a>'
+);
+assert(
+  xhtmlDoc.toString(),
+  '<?xml version="1.0" encoding="utf-8"?><title xmlns="http://www.w3.org/1999/xhtml"><a>sub element</a></title>'
+);
+assert(xhtmlDoc.querySelectorAll('a').length, 1);