Add missing test

tests/html/safeHTML.test.js

@@ -4,6 +4,17 @@ require('jsdom-global')();
 
 import { safeHTML } from '../../client/homebrew/brewRenderer/safeHTML';
 
+test('Exit if no document', function() {
+	const doc = document;
+	document = undefined;
+
+	const result = safeHTML('');
+
+	document = doc;
+
+	expect(result).toBe(null);
+});
+
 test('Javascript via href', function() {
 	const source = `<a href="javascript:alert('This is a JavaScript injection via href attribute')">Click me</a>`;
 	const rendered = safeHTML(source);