feat: add basic jest support (#35080)

PR Close #35080

packages/zone.js/lib/jest/jest.ts

@@ -0,0 +1,124 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+'use strict';
+
+Zone.__load_patch('jest', (context: any, Zone: ZoneType) => {
+  if (typeof jest === 'undefined' || jest['__zone_patch__']) {
+    return;
+  }
+
+  jest['__zone_patch__'] = true;
+
+
+  if (typeof Zone === 'undefined') {
+    throw new Error('Missing Zone.js');
+  }
+
+  const ProxyZoneSpec = (Zone as any)['ProxyZoneSpec'];
+  const SyncTestZoneSpec = (Zone as any)['SyncTestZoneSpec'];
+
+  if (!ProxyZoneSpec) {
+    throw new Error('Missing ProxyZoneSpec');
+  }
+
+  const rootZone = Zone.current;
+  const syncZone = rootZone.fork(new SyncTestZoneSpec('jest.describe'));
+  const proxyZone = rootZone.fork(new ProxyZoneSpec());
+
+  function wrapDescribeFactoryInZone(originalJestFn: Function) {
+    return function(this: unknown, ...tableArgs: any[]) {
+      const originalDescribeFn = originalJestFn.apply(this, tableArgs);
+      return function(this: unknown, ...args: any[]) {
+        args[1] = wrapDescribeInZone(args[1]);
+        return originalDescribeFn.apply(this, args);
+      };
+    };
+  }
+
+  function wrapTestFactoryInZone(originalJestFn: Function) {
+    return function(this: unknown, ...tableArgs: any[]) {
+      const testFn = originalJestFn.apply(this, tableArgs);
+      return function(this: unknown, ...args: any[]) {
+        args[1] = wrapTestInZone(args[1]);
+        return testFn.apply(this, args);
+      };
+    };
+  }
+
+  /**
+   * Gets a function wrapping the body of a jest `describe` block to execute in a
+   * synchronous-only zone.
+   */
+  function wrapDescribeInZone(describeBody: Function): Function {
+    return function(this: unknown, ...args: any[]) {
+      return syncZone.run(describeBody, this, args);
+    };
+  }
+
+  /**
+   * Gets a function wrapping the body of a jest `it/beforeEach/afterEach` block to
+   * execute in a ProxyZone zone.
+   * This will run in the `testProxyZone`.
+   */
+  function wrapTestInZone(testBody: Function): Function {
+    if (typeof testBody !== 'function') {
+      return testBody;
+    }
+    // The `done` callback is only passed through if the function expects at least one argument.
+    // Note we have to make a function with correct number of arguments, otherwise jest will
+    // think that all functions are sync or async.
+    return function(this: unknown, ...args: any[]) { return proxyZone.run(testBody, this, args); };
+  }
+
+  ['describe', 'xdescribe', 'fdescribe'].forEach(methodName => {
+    let originalJestFn: Function = context[methodName];
+    if (context[Zone.__symbol__(methodName)]) {
+      return;
+    }
+    context[Zone.__symbol__(methodName)] = originalJestFn;
+    context[methodName] = function(this: unknown, ...args: any[]) {
+      args[1] = wrapDescribeInZone(args[1]);
+      return originalJestFn.apply(this, args);
+    };
+    context[methodName].each = wrapDescribeFactoryInZone((originalJestFn as any).each);
+  });
+  context.describe.only = context.fdescribe;
+  context.describe.skip = context.xdescribe;
+
+  ['it', 'xit', 'fit', 'test', 'xtest'].forEach(methodName => {
+    let originalJestFn: Function = context[methodName];
+    if (context[Zone.__symbol__(methodName)]) {
+      return;
+    }
+    context[Zone.__symbol__(methodName)] = originalJestFn;
+    context[methodName] = function(this: unknown, ...args: any[]) {
+      args[1] = wrapTestInZone(args[1]);
+      return originalJestFn.apply(this, args);
+    };
+    context[methodName].each = wrapTestFactoryInZone((originalJestFn as any).each);
+    context[methodName].todo = (originalJestFn as any).todo;
+  });
+
+  context.it.only = context.fit;
+  context.it.skip = context.xit;
+  context.test.only = context.fit;
+  context.test.skip = context.xit;
+
+  ['beforeEach', 'afterEach', 'beforeAll', 'afterAll'].forEach(methodName => {
+    let originalJestFn: Function = context[methodName];
+    if (context[Zone.__symbol__(methodName)]) {
+      return;
+    }
+    context[Zone.__symbol__(methodName)] = originalJestFn;
+    context[methodName] = function(this: unknown, ...args: any[]) {
+      args[0] = wrapTestInZone(args[0]);
+      return originalJestFn.apply(this, args);
+    };
+  });
+});