Support generators in tests via coMocha, instead of custom code

* coMocha offers better error stack trace

.babelrc

@@ -11,7 +11,8 @@
     "resource/react-dom.js",
     "resource/bluebird.js",
     "test/resource/httpd.js",
-    "test/resource/mocha.js"
+    "test/resource/mocha.js",
+    "test/resource/co-mocha.js"
   ],
   "plugins": [
     "syntax-flow",

package.json

@@ -33,6 +33,7 @@
     "browserify": "^14.3.0",
     "chai": "^3.5.0",
     "chai-as-promised": "^6.0.0",
+    "co-mocha": "^1.2.0",
     "del": "^2.2.2",
     "glob": "^7.1.2",
     "gulp": "^3.9.1",

test/content/runtests.html

@@ -9,6 +9,7 @@
 	<script src="resource://zotero-unit/chai.js"></script>
 	<script src="resource://zotero-unit/chai-as-promised.js"></script>
 	<script src="resource://zotero-unit/mocha.js"></script>
+	<script src="resource://zotero-unit/co-mocha.js"></script>
 	<script src="resource://zotero-unit/sinon.js"></script>
 	<script src="resource://zotero-unit/pako_inflate.js"></script>
 	<script src="support.js" type="application/javascript;version=1.8"></script>

test/content/runtests.js

@@ -184,19 +184,7 @@ mocha.setup({
 	grep: ZoteroUnit.grep
 });
 
-// Enable Bluebird generator support in Mocha
-(function () {
-	var Runnable = Mocha.Runnable;
-	var run = Runnable.prototype.run;
-	Runnable.prototype.run = function (fn) {
-		if (this.fn.constructor.name === 'GeneratorFunction') {
-			this.fn = Zotero.Promise.coroutine(this.fn);
-		} else if (typeof this.fn == 'function' && this.fn.isGenerator()) {
-			throw new Error("Attempting to use a legacy generator in Mocha test");
-		}
-		return run.call(this, fn);
-	};
-})();
+coMocha(Mocha);
 
 before(function () {
 	// Store all prefs set in runtests.sh

test/resource/co-mocha.js

@@ -0,0 +1 @@
+../../node_modules/co-mocha/co-mocha.js