Added partial unit tests for host_controller.js. More to come.

remoting/webapp/crd/js/mock_xhr.js

Index: remoting/webapp/crd/js/mock_xhr.js
diff --git a/remoting/webapp/crd/js/mock_xhr.js b/remoting/webapp/crd/js/mock_xhr.js
index 706badbf82fbc69d44afc39953c51a52606a9ec2..4fa5954acd8e798e5ad2bbb490243fe7023f6f23 100644
--- a/remoting/webapp/crd/js/mock_xhr.js
+++ b/remoting/webapp/crd/js/mock_xhr.js
@@ -184,12 +184,14 @@ remoting.MockXhr.setResponseFor = function(
  *
  * @param {?string} method
  * @param {?string|!RegExp} urlPattern
+ * @param {number=} opt_status
  * @param {boolean=} opt_reuse
  */
-remoting.MockXhr.setEmptyResponseFor = function(method, urlPattern, opt_reuse) {
+remoting.MockXhr.setEmptyResponseFor = function(
+    method, urlPattern, opt_status, opt_reuse) {
   remoting.MockXhr.setResponseFor(
       method, urlPattern, function(/** remoting.MockXhr */ xhr) {
-        xhr.setEmptyResponse(204);
+        xhr.setEmptyResponse(opt_status == null ? 204 : opt_status);

[Jamie, 2015/04/07 01:13:12]

For the most common invocation, opt_status will be undefined, not null. This
will work, but I think it would be clearer if you compare to undefined. == is
still probably preferable to === though.

[John Williams, 2015/04/07 20:10:26]

In google3 I'd use goog.isDef, but here I've been using "== null" to test for
undefined in cases where null is either not allowed or it should be treated the
same as undefined.  For future reference, would you prefer "=== undefined" in
those cases?

[Jamie, 2015/04/08 00:16:14]

I guess the question here is whether or not we want to explicitly allow:

  setEmptyResponseFor(method, pattern, null)

in place of:

  setEmptyResponseFor(method, pattern)

I can't think of any reason why a caller would want to write that (maybe if they
wanted to set opt_reuse but not opt_status, but even then undefined would be
more "correct") so I lean towards using '=== undefined' and having the code fail
is the caller passes null. If you want to be more lenient, then '== undefined'
is acceptable, but I feel that '== null' is misleading as to the expected value
of omitted parameters.

       }, opt_reuse);
 };