test(option.prefixHeaderId): add tests for prefixHeaderId option

test/node/Container/testMakeHtml.js

@@ -45,6 +45,25 @@
     });
   });
 
+  describe('Converter.options prefixHeaderId', function () {
+    var converter = new showdown.Converter(),
+        text = 'foo header';
+
+    it('should prefix header id with "section"', function () {
+      converter.setOption('prefixHeaderId', true);
+      var html = converter.makeHtml('# ' + text),
+          expectedHtml = '<h1 id="sectionfooheader">' + text + '</h1>';
+      html.should.equal(expectedHtml);
+    });
+
+    it('should prefix header id with custom string', function () {
+      converter.setOption('prefixHeaderId', 'blabla');
+      var html = converter.makeHtml('# ' + text),
+          expectedHtml = '<h1 id="blablafooheader">' + text + '</h1>';
+      html.should.equal(expectedHtml);
+    });
+  });
+
   function filter() {
     return function (file) {
       var ext = file.slice(-3);