Enable the CTA experiment on all environments (#10432)

config/default.js

@@ -430,5 +430,6 @@ module.exports = {
     // See: https://github.com/mozilla/addons-frontend/pull/9125#issuecomment-580683288
     //
     // e.g., 20200204_installWarning: true,
+    '20210404_download_cta_experiment': true,
   },
 };

config/dev.js

@@ -46,8 +46,4 @@ module.exports = {
   extensionWorkshopUrl: 'https://extensionworkshop-dev.allizom.org',
 
   enableFeatureLinkToNewBlog: true,
-
-  experiments: {
-    '20210404_download_cta_experiment': true,
-  },
 };

config/development.js

@@ -83,8 +83,4 @@ module.exports = {
   extensionWorkshopUrl: 'https://extensionworkshop-dev.allizom.org',
 
   enableFeatureLinkToNewBlog: true,
-
-  experiments: {
-    '20210404_download_cta_experiment': true,
-  },
 };

config/test.js

@@ -10,4 +10,9 @@ module.exports = {
   enableRequestID: false,
 
   mozillaUserId: 1337,
+  
+  // Because tests run on the server by default and experiments are client-side
+  // only, we don't want to have any active experiments. Otherwise tests try to
+  // send an enrollment event, which triggers an exception.
+  experiments: null,
 };

jest.config.js

@@ -10,6 +10,8 @@ module.exports = {
   moduleNameMapper: {
     // Alias tests for tests to be able to import helpers.
     '^tests/(.*)$': '<rootDir>/tests/$1',
+    // Alias config for tests to be able to import config files.
+    '^config/(.*)$': '<rootDir>/config/$1',
     // Replaces the following formats with an empty module.
     '^.+\\.(scss|css|svg|woff|woff2|mp4|webm)$': '<rootDir>/tests/emptyModule',
     // Alias bin for bin scripts.

src/amo/utils/server.js

@@ -36,7 +36,7 @@ export const viewFrontendVersionHandler = ({
       };
     }, {});
 
-  const experiments = _config.get('experiments');
+  const experiments = _config.get('experiments') || {};
 
   return (req: typeof $Request, res: typeof $Response) => {
     fs.stat(version, async (error) => {

src/amo/withExperiment.js

@@ -125,7 +125,8 @@ export const isExperimentEnabled = ({
   _config: typeof config,
   id: string,
 |}): boolean => {
-  return _config.get('experiments')[id] === true;
+  const experiments = _config.get('experiments') || {};
+  return experiments[id] === true;
 };
 
 type withExperimentInternalProps = {|

tests/unit/amo/test_withExperiment.js

@@ -1,4 +1,3 @@
-import config from 'config';
 import { shallow } from 'enzyme';
 import * as React from 'react';
 
@@ -11,6 +10,8 @@ import {
   getVariant,
   withExperiment,
 } from 'amo/withExperiment';
+// eslint-disable-next-line import/namespace
+import * as defaultConfig from 'config/default';
 import {
   createFakeTracking,
   fakeCookies,
@@ -406,6 +407,13 @@ describe(__filename, () => {
     expect(root).toHaveProp('isExperimentEnabled', false);
   });
 
+  it('can handle a null for experiments in the config', () => {
+    const configOverrides = { experiments: null };
+
+    const root = render({ configOverrides });
+    expect(root).toHaveProp('isExperimentEnabled', false);
+  });
+
   it('throws an exception for a badly formatted experimentId', () => {
     expect(() => {
       render({ experimentProps: { id: 'bad-id' } });
@@ -415,7 +423,8 @@ describe(__filename, () => {
   it('does not have any invalid experiment ids defined in the config', () => {
     // If this test fails it is because an experimentId does not match the
     // expected format of YYYYMMDD_ExperimentName.
-    for (const experimentId of Object.keys(config.get('experiments'))) {
+    // eslint-disable-next-line import/namespace
+    for (const experimentId of Object.keys(defaultConfig.experiments)) {
       expect(EXPERIMENT_ID_REGEXP.test(experimentId)).toEqual(true);
     }
   });