Use Jest's built-in slowTestThreshold for detecting slow tests

jest.config.base.js

@@ -169,6 +169,7 @@ module.exports = (path, options = {}) => {
     resolver: './jest_resolver.js',
     setupFilesAfterEnv: [`<rootDir>/${path}/test_setup.js`, 'jest-canvas-mock'],
     restoreMocks: true,
+    slowTestThreshold: process.env.CI ? 6000 : 500,
     transform: {
       '^.+\\.(gql|graphql)$': 'jest-transform-graphql',
       '^.+_worker\\.js$': './spec/frontend/__helpers__/web_worker_transformer.js',

spec/frontend/__helpers__/timeout.js

-const NS_PER_SEC = 1e9;
-const NS_PER_MS = 1e6;
-const IS_DEBUGGING = process.execArgv.join(' ').includes('--inspect-brk');
-
-let testTimeoutNS;
-
-export const setTestTimeout = (newTimeoutMS) => {
-  const newTimeoutNS = newTimeoutMS * NS_PER_MS;
-  // never accept a smaller timeout than the default
-  if (newTimeoutNS < testTimeoutNS) {
-    return;
-  }
-
-  testTimeoutNS = newTimeoutNS;
-  jest.setTimeout(newTimeoutMS);
-};
-
-// Allows slow tests to set their own timeout.
-// Useful for tests with jQuery, which is very slow in big DOMs.
-let temporaryTimeoutNS = null;
-export const setTestTimeoutOnce = (newTimeoutMS) => {
-  const newTimeoutNS = newTimeoutMS * NS_PER_MS;
-  // never accept a smaller timeout than the default
-  if (newTimeoutNS < testTimeoutNS) {
-    return;
-  }
-
-  temporaryTimeoutNS = newTimeoutNS;
-};
-
-export const initializeTestTimeout = (defaultTimeoutMS) => {
-  setTestTimeout(defaultTimeoutMS);
-
-  let testStartTime;
-
-  // https://github.com/facebook/jest/issues/6947
-  beforeEach(() => {
-    testStartTime = process.hrtime();
-  });
-
-  afterEach(() => {
-    let timeoutNS = testTimeoutNS;
-    if (Number.isFinite(temporaryTimeoutNS)) {
-      timeoutNS = temporaryTimeoutNS;
-      temporaryTimeoutNS = null;
-    }
-
-    const [seconds, remainingNs] = process.hrtime(testStartTime);
-    const elapsedNS = seconds * NS_PER_SEC + remainingNs;
-
-    // Disable the timeout error when debugging. It is meaningless because
-    // debugging always takes longer than the test timeout.
-    if (elapsedNS > timeoutNS && !IS_DEBUGGING) {
-      throw new Error(
-        `Test took too long (${elapsedNS / NS_PER_MS}ms > ${timeoutNS / NS_PER_MS}ms)!`,
-      );
-    }
-  });
-};

spec/frontend/test_setup.js

@@ -2,9 +2,6 @@
 // eslint-disable-next-line no-restricted-syntax
 import { setImmediate } from 'timers';
 import 'helpers/shared_test_setup';
-import { initializeTestTimeout } from 'helpers/timeout';
-
-initializeTestTimeout(process.env.CI ? 6000 : 500);
 
 afterEach(() =>
   // give Promises a bit more time so they fail the right test