Add support for writing unit tests for Mojo-backed apps/extensions APIs.

extensions/test/data/unit_test_environment_specific_bindings.js

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+var nativesPromise = requireAsync('testNatives');
+
+function registerHooks(api) {
+  var chromeTest = api.compiledApi;
+  var apiFunctions = api.apiFunctions;
+
+  apiFunctions.setHandleRequest('notifyPass', function() {
+    nativesPromise.then(function(natives) {
+      natives.NotifyPass();
+    });
+  });
+
+  apiFunctions.setHandleRequest('notifyFail', function(message) {
+    nativesPromise.then(function(natives) {
+      natives.NotifyFail(message);
+    });
+  });
+
+  apiFunctions.setHandleRequest('log', function() {
+    nativesPromise.then(function(natives) {
+      natives.Log($Array.join(arguments, ' '));
+    });
+  });
+
+  apiFunctions.setHandleRequest('runWithModuleSystem', function(callback) {
+    throw new Error('Not implemented');
+  });
+
+  apiFunctions.setHandleRequest('getApiDefinitions', function() {
+    throw new Error('Not implemented');
+  });
+
+  apiFunctions.setHandleRequest('getApiFeatures', function() {
+    throw new Error('Not implemented');
+  });
+
+  apiFunctions.setHandleRequest('isProcessingUserGesture', function() {
+    throw new Error('Not implemented');
+  });
+
+  apiFunctions.setHandleRequest('runWithUserGesture', function(callback) {
+    throw new Error('Not implemented');
+  });
+
+  apiFunctions.setHandleRequest('runWithoutUserGesture', function(callback) {
+    throw new Error('Not implemented');
+  });
+
+  apiFunctions.setHandleRequest('setExceptionHandler', function(callback) {
+    chromeTest.assertEq(typeof(callback), 'function');
+    uncaughtExceptionHandler.setHandler(callback);
+  });
+}
+
+function testDone(runNextTest) {
+    // Use a promise here to allow previous test contexts to be eligible for
+    // garbage collection.
+    Promise.resolve().then(function() {
+      runNextTest();
+    });
+}
+
+function exportTests(tests, runTests, exports) {
+  $Array.forEach(tests, function(test) {
+    exports[test.name] = function() {
+      runTests([test]);
+      return true;
+    }
+  });
+}
+
+exports.registerHooks = registerHooks;
+exports.testDone = testDone;
+exports.exportTests = exportTests;