Fail long running tests

jest.config.js

@@ -24,4 +24,5 @@ module.exports = {
   cacheDirectory: '<rootDir>/tmp/cache/jest',
   modulePathIgnorePatterns: ['<rootDir>/.yarn-cache/'],
   reporters,
+  setupTestFrameworkScriptFile: '<rootDir>/spec/frontend/test_setup.js',
 };

spec/frontend/test_setup.js

+const testTimeoutInMs = 0;
+jest.setTimeout(testTimeoutInMs);
+
+let testStartTime;
+
+// https://github.com/facebook/jest/issues/6947
+beforeEach(() => {
+  testStartTime = Date.now();
+});
+
+afterEach(() => {
+  const elapsedTimeInMs = Date.now() - testStartTime;
+  if (elapsedTimeInMs > testTimeoutInMs) {
+    throw new Error(`Test took too long (${elapsedTimeInMs}ms > ${testTimeoutInMs}ms)!`);
+  }
+});