chore: Remove dead code/config related to Mocha unit tests (#25492)

## **Description**

Our test scripts and configuration have been updated to remove things
that were used for our Mocha unit tests, which have been converted to
Jest. This unblocks the creation of a test coverage quality gate
(previously this was blocked by a bug in our "merge coverage" step,
which merged Mocha and Jest coverage).

[![Open in GitHub
Codespaces](https://github.com/codespaces/badge.svg)](https://codespaces.new/MetaMask/metamask-extension/pull/25492?quickstart=1)

## **Related issues**

None

## **Manual testing steps**

N/A

## **Screenshots/Recordings**

N/A

## **Pre-merge author checklist**

- [x] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask
Extension Coding
Standards](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've completed the PR template to the best of my ability
- [x] I’ve included tests if applicable
- [x] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [x] I’ve applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.

---------

Co-authored-by: MetaMask Bot <[email protected]>

.circleci/config.yml

@@ -236,7 +236,7 @@ workflows:
       - test-unit-jest-development:
           requires:
             - prep-deps
-      - upload-and-validate-coverage:
+      - upload-coverage:
           requires:
             - test-unit-jest-main
             - test-unit-jest-development
@@ -286,7 +286,7 @@ workflows:
             - test-unit-jest-main
             - test-unit-jest-development
             - test-unit-global
-            - upload-and-validate-coverage
+            - upload-coverage
             - validate-source-maps
             - validate-source-maps-beta
             - validate-source-maps-flask
@@ -1677,17 +1677,14 @@ jobs:
       - store_test_results:
           path: test/test-results/junit.xml
 
-  upload-and-validate-coverage:
+  upload-coverage:
     executor: node-browsers-small
     steps:
       - run: *shallow-git-clone
       - run: sudo corepack enable
       - attach_workspace:
           at: .
       - codecov/upload
-      - run:
-          name: test:coverage:validate
-          command: yarn test:coverage:validate
       - persist_to_workspace:
           root: .
           paths:

.depcheckrc.yml

@@ -39,8 +39,6 @@ ignores:
   - 'wait-on'
   - 'tsx' # used in .devcontainer
   - 'prettier-eslint' # used by the Prettier ESLint VSCode extension
-  # development tool
-  - 'nyc'
   # storybook
   - '@storybook/cli'
   - '@storybook/core'

.eslintrc.js

@@ -46,9 +46,7 @@ module.exports = {
         'development/**/*.js',
         'test/e2e/**/*.js',
         'test/helpers/*.js',
-        'test/lib/wait-until-called.js',
         'test/run-unit-tests.js',
-        'test/merge-coverage.js',
       ],
       extends: [
         path.resolve(__dirname, '.eslintrc.base.js'),
@@ -94,8 +92,6 @@ module.exports = {
         'test/stub/**/*.js',
         'test/unit-global/**/*.js',
       ],
-      // TODO: Convert these files to modern JS
-      excludedFiles: ['test/lib/wait-until-called.js'],
       extends: [
         path.resolve(__dirname, '.eslintrc.base.js'),
         path.resolve(__dirname, '.eslintrc.node.js'),
@@ -261,30 +257,7 @@ module.exports = {
      * Mocha library.
      */
     {
-      files: [
-        '**/*.test.js',
-        'test/lib/wait-until-called.js',
-        'test/e2e/**/*.spec.js',
-      ],
-      excludedFiles: [
-        'app/scripts/controllers/app-state.test.js',
-        'app/scripts/controllers/mmi-controller.test.js',
-        'app/scripts/metamask-controller.actions.test.js',
-        'app/scripts/detect-multiple-instances.test.js',
-        'app/scripts/controllers/swaps.test.js',
-        'app/scripts/controllers/metametrics.test.js',
-        'app/scripts/controllers/permissions/**/*.test.js',
-        'app/scripts/controllers/preferences.test.js',
-        'app/scripts/lib/**/*.test.js',
-        'app/scripts/metamask-controller.test.js',
-        'app/scripts/migrations/*.test.js',
-        'app/scripts/platforms/*.test.js',
-        'development/**/*.test.js',
-        'shared/**/*.test.js',
-        'ui/**/*.test.js',
-        'ui/__mocks__/*.js',
-        'test/e2e/helpers.test.js',
-      ],
+      files: ['test/e2e/**/*.spec.js', 'test/unit-global/*.test.js'],
       extends: ['@metamask/eslint-config-mocha'],
       rules: {
         // In Mocha tests, it is common to use `this` to store values or do
@@ -297,7 +270,9 @@ module.exports = {
      * Jest tests
      *
      * These are files that make use of globals and syntax introduced by the
-     * Jest library. The files in this section should match the Mocha excludedFiles section.
+     * Jest library.
+     * TODO: This list of files is incomplete, and should be replaced with globs that match the
+     * Jest config.
      */
     {
       files: [
@@ -391,7 +366,6 @@ module.exports = {
         'test/e2e/benchmark.js',
         'test/helpers/setup-helper.js',
         'test/run-unit-tests.js',
-        'test/merge-coverage.js',
       ],
       rules: {
         'node/no-process-exit': 'off',

.mocharc.js

@@ -1,23 +1,6 @@
 module.exports = {
   // TODO: Remove the `exit` setting, it can hide broken tests.
   exit: true,
-  ignore: [
-    './app/scripts/lib/**/*.test.js',
-    './app/scripts/migrations/*.test.js',
-    './app/scripts/platforms/*.test.js',
-    './app/scripts/controllers/app-state.test.js',
-    './app/scripts/controllers/permissions/**/*.test.js',
-    './app/scripts/controllers/mmi-controller.test.ts',
-    './app/scripts/metamask-controller.actions.test.js',
-    './app/scripts/detect-multiple-instances.test.js',
-    './app/scripts/controllers/swaps.test.js',
-    './app/scripts/controllers/metametrics.test.js',
-    './app/scripts/controllers/preferences.test.js',
-    './app/scripts/constants/error-utils.test.js',
-    './app/scripts/metamask-controller.test.js',
-    './development/fitness-functions/**/*.test.ts',
-    './test/e2e/helpers.test.js',
-  ],
   recursive: true,
   require: ['test/env.js', 'test/setup.js'],
 };

development/ts-migration-dashboard/files-to-convert.json

@@ -316,7 +316,6 @@
   "test/lib/mock-encryptor.js",
   "test/lib/render-helpers.js",
   "test/lib/tick.js",
-  "test/lib/wait-until-called.js",
   "test/mocks/permissions.js",
   "test/stub/provider.js",
   "test/stub/tx-meta-stub.js",