feat: add test helper for stubbing services

Author: alexlafroscia

.eslintrc.js

@@ -2,47 +2,46 @@ module.exports = {
   root: true,
   parserOptions: {
     ecmaVersion: 2017,
-    sourceType: 'module'
+    sourceType: "module"
   },
-  plugins: [
-    'ember'
-  ],
-  extends: [
-    'eslint:recommended',
-    'plugin:ember/recommended'
-  ],
+  plugins: ["ember"],
+  extends: ["eslint:recommended", "plugin:ember/recommended"],
   env: {
     browser: true
   },
-  rules: {
-  },
+  rules: {},
   overrides: [
     // node files
     {
       files: [
-        'index.js',
-        'testem.js',
-        'ember-cli-build.js',
-        'config/**/*.js',
-        'tests/dummy/config/**/*.js'
+        "index.js",
+        "testem.js",
+        "ember-cli-build.js",
+        "config/**/*.js",
+        "tests/dummy/config/**/*.js"
       ],
       excludedFiles: [
-        'app/**',
-        'addon/**',
-        'tests/dummy/app/**'
+        "app/**",
+        "addon/**",
+        "tests/dummy/app/**",
+        "addon-test-support/**"
       ],
       parserOptions: {
-        sourceType: 'script',
+        sourceType: "script",
         ecmaVersion: 2015
       },
       env: {
         browser: false,
         node: true
       },
-      plugins: ['node'],
-      rules: Object.assign({}, require('eslint-plugin-node').configs.recommended.rules, {
-        // add your custom rules and overrides for node files here
-      })
+      plugins: ["node"],
+      rules: Object.assign(
+        {},
+        require("eslint-plugin-node").configs.recommended.rules,
+        {
+          // add your custom rules and overrides for node files here
+        }
+      )
     }
   ]
 };

README.md

@@ -14,7 +14,30 @@ Then import as follows:
 import td from 'testdouble';
 ```
 
-License
-------------------------------------------------------------------------------
+## Test Helpers
+
+### `stubService`
+
+Included is a function that can replace a service with one stubbed using [`td.object()`][td-object].
+
+```js
+import td from "testdouble";
+import { stubService } from "ember-cli-testdouble/test-support";
+
+test("verifying a method invocation", function(assert) {
+  assert.expect(0); // Won't actually use `assert` in this test
+
+  stubService("some-service");
+
+  let someService = this.owner.lookup("service:some-service");
+  someService.method();
+
+  td.verify(someService.method()); // Passes!
+});
+```
+
+## License
 
 This project is licensed under the [MIT License](LICENSE.md).
+
+[td-object]: https://github.com/testdouble/testdouble.js/blob/master/docs/4-creating-test-doubles.md#tdobject

addon-test-support/index.js

@@ -0,0 +1 @@
+export { default as stubService } from "./stub-service";

addon-test-support/stub-service.js

@@ -0,0 +1,42 @@
+import { getContext } from "@ember/test-helpers";
+import { run } from "@ember/runloop";
+import td from "testdouble";
+
+function replace(owner, name) {
+  const serviceName = `service:${name}`;
+  const original = owner.lookup(serviceName);
+  const replacement = td.object(original);
+
+  run(() => {
+    owner.unregister(serviceName);
+    owner.register(serviceName, replacement, { instantiate: false });
+  });
+
+  return replacement;
+}
+
+/**
+ * Replace a service with a stubbed version of itself
+ *
+ * Each method on the service will be replaced with a TestDouble function
+ */
+export default function stubService() {
+  if (arguments.length === 2) {
+    let [hooks, name] = arguments;
+
+    hooks.beforeEach(function() {
+      replace(this.owner, name);
+    });
+
+    hooks.afterEach(function() {
+      td.reset();
+    });
+  } else if (arguments.length === 1) {
+    let [name] = arguments;
+    let { owner } = getContext();
+
+    replace(owner, name);
+  } else {
+    throw new Error("Unexpected number of arguments");
+  }
+}

package.json

@@ -42,6 +42,7 @@
     "ember-cli-qunit": "^4.1.1",
     "ember-cli-shims": "^1.2.0",
     "ember-cli-sri": "^2.1.0",
+    "ember-cli-testdouble-qunit": "^2.0.2",
     "ember-cli-uglify": "^2.0.0",
     "ember-disable-prototype-extensions": "^1.1.2",
     "ember-export-application-global": "^2.0.0",

tests/dummy/app/services/to-stub.js

@@ -0,0 +1,7 @@
+import Service from "@ember/service";
+
+export default Service.extend({
+  method() {
+    // This will be stubbed in a test
+  }
+});

tests/test-helper.js

@@ -1,7 +1,9 @@
-import Application from '../app';
-import config from '../config/environment';
-import { setApplication } from '@ember/test-helpers';
-import { start } from 'ember-qunit';
+import Application from "../app";
+import config from "../config/environment";
+import { setApplication } from "@ember/test-helpers";
+import { start } from "ember-qunit";
+
+import "ember-cli-testdouble-qunit";
 
 setApplication(Application.create(config.APP));
 

tests/unit/test-support/stub-service-test.js

@@ -0,0 +1,31 @@
+import { module, test } from "qunit";
+import { setupTest } from "ember-qunit";
+import { stubService } from "ember-cli-testdouble/test-support";
+
+module("Test Helpers | stub-service", function(hooks) {
+  setupTest(hooks);
+
+  module("as a `hooks` reciever", function(hooks) {
+    stubService(hooks, "to-stub");
+
+    test("it can replace a service", function(assert) {
+      let service = this.owner.lookup("service:to-stub");
+      service.method();
+
+      assert.verify(service.method());
+    });
+  });
+
+  module("invoking without `hooks`", function(hooks) {
+    hooks.beforeEach(function() {
+      stubService("to-stub");
+    });
+
+    test("it can replace a service", function(assert) {
+      let service = this.owner.lookup("service:to-stub");
+      service.method();
+
+      assert.verify(service.method());
+    });
+  });
+});

yarn.lock

@@ -2071,6 +2071,14 @@ ember-cli-test-loader@^2.2.0:
   dependencies:
     ember-cli-babel "^6.8.1"
 
+ember-cli-testdouble-qunit@^2.0.2:
+  version "2.0.2"
+  resolved "https://registry.yarnpkg.com/ember-cli-testdouble-qunit/-/ember-cli-testdouble-qunit-2.0.2.tgz#4edbe71e71d1abff101cb36e780a24586e8ba829"
+  dependencies:
+    broccoli-funnel "^2.0.1"
+    ember-cli-babel "^6.6.0"
+    testdouble-qunit "^2.0.2"
+
 ember-cli-uglify@^2.0.0:
   version "2.0.2"
   resolved "https://registry.yarnpkg.com/ember-cli-uglify/-/ember-cli-uglify-2.0.2.tgz#12becdaf1a2e6f0cdbd386b1d5f5a2d0540347d3"
@@ -5896,6 +5904,10 @@ temp@0.8.3:
     os-tmpdir "^1.0.0"
     rimraf "~2.2.6"
 
+testdouble-qunit@^2.0.2:
+  version "2.0.2"
+  resolved "https://registry.yarnpkg.com/testdouble-qunit/-/testdouble-qunit-2.0.2.tgz#740393c867901b9a814882b50f4c94a9e343fab9"
+
 testdouble@^3.5.2:
   version "3.5.2"
   resolved "https://registry.yarnpkg.com/testdouble/-/testdouble-3.5.2.tgz#7ac91d08be05bac3b2acba57c430f6c62d0ad8af"