Added test case for unsupported type

test/views/attachment_view.js

@@ -0,0 +1,11 @@
+describe('AttachmentView', function() {
+
+  it('should display an error for an unsupported type', function() {
+    var attachment = {
+      contentType: 'html/text';
+    }
+    var view = new Whisper.AttachmentView({model: attachment}).render();
+    assert.match(view.$el.text(), /Sorry, your attachment has a type, html, that is not currently supported./);
+  });
+
+});