Bug 1510545 - Move mock support to browser-loader and shared test helper;r=ochameau,ladybenko

Differential Revision: https://phabricator.services.mozilla.com/D13751

--HG--
extra : moz-landing-system : lando

devtools/client/aboutdebugging-new/src/modules/moz.build

@@ -11,6 +11,5 @@ DevToolsModules(
     'network-locations.js',
     'runtime-client-factory.js',
     'runtimes-state-helper.js',
-    'test-helper.js',
     'usb-runtimes.js',
 )

devtools/client/aboutdebugging-new/src/modules/runtime-client-factory.js

@@ -55,5 +55,3 @@ async function createClientForRuntime(runtime) {
 }
 
 exports.createClientForRuntime = createClientForRuntime;
-
-require("./test-helper").enableMocks(module, "modules/runtime-client-factory");

devtools/client/aboutdebugging-new/src/modules/test-helper.js

@@ -1,84 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-"use strict";
-
-const flags = require("devtools/shared/flags");
-
-/**
- * The methods from this module are going to be called from both aboutdebugging
- * BrowserLoader modules (enableMocks) and from tests (setMockedModules,
- * removeMockedModule). We use the main devtools loader to communicate between the
- * different sandboxes involved.
- */
-const { Cu } = require("chrome");
-const { loader } = Cu.import("resource://devtools/shared/Loader.jsm", {});
-
-const ROOT_PATH = "resource://devtools/client/aboutdebugging-new/src/";
-
-/**
- * Allows to load a mock instead of an about:debugging module.
- * To use it, the module to mock needs to call
- *   require("devtools/client/aboutdebugging-new/src/modules/test-helper").
- *     enableMocks(module, "path/to/module.js");
- *
- * From the tests, the devtools loader should be provided with the mocked module using
- * setMockedModule().
- *
- * At the end of the test, the mocks should be discarded with removeMockedModule().
- *
- * @param {Object} moduleToMock
- *        The `module` global from the module we want to mock, in order to override its
- *        `module.exports`.
- * @param {String} modulePath
- *        Path to the module, relative to `devtools/client/aboutdebugging-new/src/`
- */
-function enableMocks(moduleToMock, modulePath) {
-  if (flags.testing) {
-    const path = ROOT_PATH + modulePath + ".js";
-    if (loader.mocks && loader.mocks[path]) {
-      moduleToMock.exports = loader.mocks[path];
-    }
-  }
-}
-exports.enableMocks = enableMocks;
-
-/**
- * Assign a mock object to the provided module path, relative to
- * `devtools/client/aboutdebugging-new/src/`.
- */
-function setMockedModule(mock, modulePath) {
-  loader.mocks = loader.mocks || {};
-  const mockedModule = {};
-  Object.keys(mock).forEach(key => {
-    if (typeof mock[key] === "function") {
-      // All the mock methods are wrapped again here so that if the test replaces the
-      // methods dynamically and call sites used
-      // `const { someMethod } = require("./runtime-client-factory")`, someMethod will
-      // still internally call the current method defined on the mock, and not the one
-      // that was defined at the moment of the import.
-      mockedModule[key] = function() {
-        return mock[key].apply(mock, arguments);
-      };
-    } else {
-      mockedModule[key] = mock[key];
-    }
-  });
-
-  const path = ROOT_PATH + modulePath + ".js";
-  loader.mocks[path] = mockedModule;
-}
-exports.setMockedModule = setMockedModule;
-
-/**
- * Remove any mock object defined for the provided module path, relative to
- * `devtools/client/aboutdebugging-new/src/`.
- */
-function removeMockedModule(modulePath) {
-  const path = ROOT_PATH + modulePath + ".js";
-  if (loader.mocks && loader.mocks[path]) {
-    delete loader.mocks[path];
-  }
-}
-exports.removeMockedModule = removeMockedModule;

devtools/client/aboutdebugging-new/src/modules/usb-runtimes.js

@@ -29,5 +29,3 @@ function refreshUSBRuntimes() {
   return adb.updateRuntimes();
 }
 exports.refreshUSBRuntimes = refreshUSBRuntimes;
-
-require("./test-helper").enableMocks(module, "modules/usb-runtimes");

devtools/client/aboutdebugging-new/test/browser/mocks/head-runtime-client-factory-mock.js

@@ -1,7 +1,6 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 /* import-globals-from ../../../../shared/test/shared-head.js */
-
 "use strict";
 
 /**
@@ -13,16 +12,18 @@
  *        - createClientForRuntime(runtime)
  */
 function enableRuntimeClientFactoryMock(mock) {
-  const { setMockedModule } = require("devtools/client/aboutdebugging-new/src/modules/test-helper");
-  setMockedModule(mock, "modules/runtime-client-factory");
+  const { setMockedModule } = require("devtools/client/shared/browser-loader-mocks");
+  setMockedModule(mock,
+    "devtools/client/aboutdebugging-new/src/modules/runtime-client-factory");
 }
 
 /**
  * Update the loader to clear the mock entry for the runtime-client-factory module.
  */
 function disableRuntimeClientFactoryMock() {
-  const { removeMockedModule } = require("devtools/client/aboutdebugging-new/src/modules/test-helper");
-  removeMockedModule("modules/runtime-client-factory");
+  const { removeMockedModule } = require("devtools/client/shared/browser-loader-mocks");
+  removeMockedModule(
+    "devtools/client/aboutdebugging-new/src/modules/runtime-client-factory");
 }
 
 /**

devtools/client/aboutdebugging-new/test/browser/mocks/head-usb-runtimes-mock.js

@@ -17,16 +17,18 @@
  *        - removeUSBRuntimesObserver(listener)
  */
 function enableUsbRuntimesMock(mock) {
-  const { setMockedModule } = require("devtools/client/aboutdebugging-new/src/modules/test-helper");
-  setMockedModule(mock, "modules/usb-runtimes");
+  const { setMockedModule } = require("devtools/client/shared/browser-loader-mocks");
+  setMockedModule(mock,
+    "devtools/client/aboutdebugging-new/src/modules/usb-runtimes");
 }
 
 /**
  * Update the loader to clear the mock entry for the usb-runtimes module.
  */
 function disableUsbRuntimesMock() {
-  const { removeMockedModule } = require("devtools/client/aboutdebugging-new/src/modules/test-helper");
-  removeMockedModule("modules/usb-runtimes");
+  const { removeMockedModule } = require("devtools/client/shared/browser-loader-mocks");
+  removeMockedModule(
+    "devtools/client/aboutdebugging-new/src/modules/usb-runtimes");
 }
 
 /**

devtools/client/shared/browser-loader-mocks.js

@@ -0,0 +1,72 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+// Map of mocked modules, keys are absolute URIs for devtools modules such as
+// "resource://devtools/path/to/mod.js, values are objects (anything passed to
+// setMockedModule technically).
+const _mocks = {};
+
+/**
+ * Retrieve a mocked module matching the provided uri, eg "resource://path/to/file.js".
+ */
+function getMockedModule(uri) {
+  return _mocks[uri];
+}
+exports.getMockedModule = getMockedModule;
+
+/**
+ * Module paths are transparently provided with or without ".js" when using the loader,
+ * normalize the user-provided module paths to always have modules ending with ".js".
+ */
+function _getUriForModulePath(modulePath) {
+  // Assume js modules and add the .js extension if missing.
+  if (!modulePath.endsWith(".js")) {
+    modulePath = modulePath + ".js";
+  }
+
+  // Add resource:// scheme if no scheme is specified.
+  if (!modulePath.includes("://")) {
+    modulePath =  "resource://" + modulePath;
+  }
+
+  return modulePath;
+}
+
+/**
+ * Assign a mock object to the provided module path.
+ * @param mock
+ *        Plain JavaScript object that will implement the expected API for the mocked
+ *        module.
+ * @param modulePath
+ *        The module path should be the absolute module path, starting with `devtools`:
+ *        "devtools/client/some-panel/some-module"
+ */
+function setMockedModule(mock, modulePath) {
+  const uri = _getUriForModulePath(modulePath);
+  _mocks[uri] = new Proxy(mock, {
+    get(target, key) {
+      if (typeof target[key] === "function") {
+        // Functions are wrapped to be able to update the methods during the test, even if
+        // the methods were imported with destructuring. For instance:
+        //   `const { someMethod } = require("./my-module");`
+        return function() {
+          return target[key].apply(target, arguments);
+        };
+      }
+      return target[key];
+    },
+  });
+}
+exports.setMockedModule = setMockedModule;
+
+/**
+ * Remove any mock object defined for the provided absolute module path.
+ */
+function removeMockedModule(modulePath) {
+  const uri = _getUriForModulePath(modulePath);
+  delete _mocks[uri];
+}
+exports.removeMockedModule = removeMockedModule;

devtools/client/shared/browser-loader.js

@@ -4,11 +4,18 @@
 "use strict";
 
 const loaders = ChromeUtils.import("resource://devtools/shared/base-loader.js", {});
-const { devtools } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
+const {
+  devtools,
+  loader,
+} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
+const flags = devtools.require("devtools/shared/flags");
 const { joinURI } = devtools.require("devtools/shared/path");
 const { assert } = devtools.require("devtools/shared/DevToolsUtils");
 const { AppConstants } = devtools.require("resource://gre/modules/AppConstants.jsm");
 
+loader.lazyRequireGetter(this, "getMockedModule",
+  "devtools/client/shared/browser-loader-mocks", {});
+
 const BROWSER_BASED_DIRS = [
   "resource://devtools/client/inspector/boxmodel",
   "resource://devtools/client/inspector/changes",
@@ -128,6 +135,13 @@ function BrowserLoaderBuilder({ baseURI, window, useOnlyShared, commonLibRequire
 
       const uri = require.resolve(id);
 
+      // The mocks can be set from tests using browser-loader-mocks.js setMockedModule().
+      // If there is an entry for a given uri in the `mocks` object, return it instead of
+      // requiring the module.
+      if (flags.testing && getMockedModule(uri)) {
+        return getMockedModule(uri);
+      }
+
       if (commonLibRequire && COMMON_LIBRARY_DIRS.some(dir => uri.startsWith(dir))) {
         return commonLibRequire(uri);
       }

devtools/client/shared/moz.build

@@ -22,6 +22,7 @@ DIRS += [
 
 DevToolsModules(
     'autocomplete-popup.js',
+    'browser-loader-mocks.js',
     'browser-loader.js',
     'css-angle.js',
     'curl.js',

devtools/client/shared/test/browser.ini

@@ -59,12 +59,14 @@ support-files =
   telemetry-test-helpers.js
   test-actor-registry.js
   test-actor.js
+  test-mocked-module.js
   testactors.js
   !/devtools/client/responsive.html/test/browser/devices.json
   !/devtools/client/debugger/new/test/mochitest/helpers.js
   !/devtools/client/debugger/new/test/mochitest/helpers/context.js
 
 [browser_autocomplete_popup.js]
+[browser_browserloader_mocks.js]
 [browser_css_angle.js]
 [browser_css_color.js]
 [browser_cubic-bezier-01.js]

devtools/client/shared/test/browser_browserloader_mocks.js

@@ -0,0 +1,106 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { BrowserLoader } =
+  ChromeUtils.import("resource://devtools/client/shared/browser-loader.js", {});
+
+const { getMockedModule, setMockedModule, removeMockedModule } =
+  require("devtools/client/shared/browser-loader-mocks");
+const { require: browserRequire } = BrowserLoader({
+  baseURI: "resource://devtools/client/shared/",
+  window,
+});
+
+// Check that modules can be mocked in the browser loader.
+// Test with a custom test module under the chrome:// scheme.
+function testWithChromeScheme() {
+  // Full chrome URI for the test module.
+  const CHROME_URI = CHROME_URL_ROOT + "test-mocked-module.js";
+  const ORIGINAL_VALUE = "Original value";
+  const MOCKED_VALUE_1 = "Mocked value 1";
+  const MOCKED_VALUE_2 = "Mocked value 2";
+
+  const m1 = browserRequire(CHROME_URI);
+  ok(m1, "Regular module can be required");
+  is(m1.methodToMock(), ORIGINAL_VALUE, "Method returns the expected value");
+  is(m1.someProperty, "someProperty", "Property has the expected value");
+
+  info("Create a simple mocked version of the test module");
+  const mockedModule = {
+    methodToMock: () => MOCKED_VALUE_1,
+    someProperty: "somePropertyMocked",
+  };
+  setMockedModule(mockedModule, CHROME_URI);
+  ok(!!getMockedModule(CHROME_URI), "Has an entry for the chrome URI.");
+
+  const m2 = browserRequire(CHROME_URI);
+  ok(m2, "Mocked module can be required via chrome URI");
+  is(m2.methodToMock(), MOCKED_VALUE_1, "Mocked method returns the expected value");
+  is(m2.someProperty, "somePropertyMocked", "Mocked property has the expected value");
+
+  const { methodToMock: requiredMethod } = browserRequire(CHROME_URI);
+  ok(requiredMethod() === MOCKED_VALUE_1,
+    "Mocked method returns the expected value when imported with destructuring");
+
+  info("Update the mocked method to return a different value");
+  mockedModule.methodToMock = () => MOCKED_VALUE_2;
+  is(requiredMethod(), MOCKED_VALUE_2,
+    "Mocked method returns the updated value  when imported with destructuring");
+
+  info("Remove the mock for the test module");
+  removeMockedModule(CHROME_URI);
+  ok(!getMockedModule(CHROME_URI), "Has no entry for the chrome URI.");
+
+  const m3 = browserRequire(CHROME_URI);
+  ok(m3, "Regular module can be required after removing the mock");
+  is(m3.methodToMock(), ORIGINAL_VALUE, "Method on module returns the expected value");
+}
+
+// Similar tests as in testWithChromeScheme, but this time with a devtools module
+// available under the resource:// scheme.
+function testWithRegularDevtoolsModule() {
+  // Testing with devtools/shared/path because it is a simple module, that can be imported
+  // with destructuring. Any other module would do.
+  const DEVTOOLS_MODULE_PATH = "devtools/shared/path";
+  const DEVTOOLS_MODULE_URI = "resource://devtools/shared/path.js";
+
+  const m1 = browserRequire(DEVTOOLS_MODULE_PATH);
+  is(m1.joinURI("http://a", "b"), "http://a/b", "Original module was required");
+
+  info("Set a mock for a sub-part of the path, which should not match require calls");
+  setMockedModule({ joinURI: () => "WRONG_PATH" }, "shared/path");
+
+  ok(!getMockedModule(DEVTOOLS_MODULE_URI), "Has no mock entry for the full URI");
+  const m2 = browserRequire(DEVTOOLS_MODULE_PATH);
+  is(m2.joinURI("http://a", "b"), "http://a/b", "Original module is still required");
+
+  info("Set a mock for the complete path, which should now match require calls");
+  const mockedModule = {
+    joinURI: () => "MOCKED VALUE",
+  };
+  setMockedModule(mockedModule, DEVTOOLS_MODULE_PATH);
+  ok(!!getMockedModule(DEVTOOLS_MODULE_URI), "Has a mock entry for the full URI.");
+
+  const m3 = browserRequire(DEVTOOLS_MODULE_PATH);
+  is(m3.joinURI("http://a", "b"), "MOCKED VALUE", "The mocked module has been returned");
+
+  info("Check that the mocked methods can be updated after a destructuring import");
+  const { joinURI } = browserRequire(DEVTOOLS_MODULE_PATH);
+  mockedModule.joinURI = () => "UPDATED VALUE";
+  is(joinURI("http://a", "b"), "UPDATED VALUE", "Mocked method was correctly updated");
+
+  removeMockedModule(DEVTOOLS_MODULE_PATH);
+  ok(!getMockedModule(DEVTOOLS_MODULE_URI), "Has no mock entry for the full URI");
+  const m4 = browserRequire(DEVTOOLS_MODULE_PATH);
+  is(m4.joinURI("http://a", "b"), "http://a/b", "Original module can be required again");
+}
+
+function test() {
+  testWithChromeScheme();
+  testWithRegularDevtoolsModule();
+  finish();
+}

devtools/client/shared/test/test-mocked-module.js

@@ -0,0 +1,11 @@
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const methodToMock = function() {
+  return "Original value";
+};
+
+exports.methodToMock = methodToMock;
+exports.someProperty = "someProperty";