Fix custom async matcher stack traces (#7652)

CHANGELOG.md

@@ -7,6 +7,7 @@
 ### Fixes
 
 - `[jest-cli]` Refactor `-o` and `--coverage` combined ([#7611](https://github.com/facebook/jest/pull/7611))
+- `[expect]` Fix custom async matcher stack trace ([#7652](https://github.com/facebook/jest/pull/7652))
 
 ### Chore & Maintenance
 

e2e/__tests__/__snapshots__/customMatcherStackTrace.test.js.snap

@@ -1,7 +1,26 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`custom async matchers 1`] = `
+FAIL __tests__/asynchronous.test.js
+  ✕ showing the stack trace for an async matcher
+
+  ● showing the stack trace for an async matcher
+
+    We expect the stack trace and code fence for this matcher to be shown in the console.
+
+       9 | 
+      10 | test('showing the stack trace for an async matcher', async () => {
+    > 11 |   await expect(true).toThrowCustomAsyncMatcherError();
+         |                      ^
+      12 | });
+      13 | 
+      14 | async function toThrowCustomAsyncMatcherError() {
+
+      at Object.toThrowCustomAsyncMatcherError (__tests__/asynchronous.test.js:11:22)
+`;
+
 exports[`works with custom matchers 1`] = `
-FAIL __tests__/customMatcher.test.js
+FAIL __tests__/sync.test.js
   Custom matcher
     ✓ passes
     ✓ fails
@@ -19,10 +38,10 @@ FAIL __tests__/customMatcher.test.js
       47 | 
       48 |     // This expecation fails due to an error we throw (intentionally)
 
-      at Error (__tests__/customMatcher.test.js:45:13)
-      at baz (__tests__/customMatcher.test.js:43:23)
-      at bar (__tests__/customMatcher.test.js:42:23)
-      at foo (__tests__/customMatcher.test.js:52:7)
-      at Object.callback (__tests__/customMatcher.test.js:11:18)
-      at Object.toCustomMatch (__tests__/customMatcher.test.js:53:8)
+      at Error (__tests__/sync.test.js:45:13)
+      at baz (__tests__/sync.test.js:43:23)
+      at bar (__tests__/sync.test.js:42:23)
+      at foo (__tests__/sync.test.js:52:7)
+      at Object.callback (__tests__/sync.test.js:11:18)
+      at Object.toCustomMatch (__tests__/sync.test.js:53:8)
 `;

e2e/__tests__/__snapshots__/expectAsyncMatcher.test.js.snap

@@ -10,22 +10,40 @@ FAIL __tests__/failure.test.js
   ● fail with expected non promise values
 
     Expected value to have length:
+      2
+    Received:
+      1
+    received.length:
+      1
+
+      11 | 
+      12 | it('fail with expected non promise values', () =>
+    > 13 |   expect([1]).toHaveLengthAsync(Promise.resolve(2)));
+         |               ^
+      14 | 
+      15 | it('fail with expected non promise values and not', () =>
+      16 |   expect([1, 2]).not.toHaveLengthAsync(Promise.resolve(2)));
 
-        2
-      Received:
-        1
-      received.length:
-        1
+      at Object.toHaveLengthAsync (__tests__/failure.test.js:13:15)
 
   ● fail with expected non promise values and not
 
     Expected value to not have length:
+      2
+    Received:
+      1,2
+    received.length:
+      2
+
+      14 | 
+      15 | it('fail with expected non promise values and not', () =>
+    > 16 |   expect([1, 2]).not.toHaveLengthAsync(Promise.resolve(2)));
+         |                      ^
+      17 | 
+      18 | it('fail with expected promise values', () =>
+      19 |   expect(Promise.resolve([1])).resolves.toHaveLengthAsync(Promise.resolve(2)));
 
-        2
-      Received:
-        1,2
-      received.length:
-        2
+      at Object.toHaveLengthAsync (__tests__/failure.test.js:16:22)
 
   ● fail with expected promise values
 
@@ -36,19 +54,15 @@ FAIL __tests__/failure.test.js
     received.length:
       1
 
-      22 | 
-      23 | it('fail with expected promise values', async () => {
-    > 24 |   await (expect(Promise.resolve([1])): any).resolves.toHaveLengthAsync(
-         |                                                      ^
-      25 |     Promise.resolve(2)
-      26 |   );
-      27 | });
+      17 | 
+      18 | it('fail with expected promise values', () =>
+    > 19 |   expect(Promise.resolve([1])).resolves.toHaveLengthAsync(Promise.resolve(2)));
+         |                                         ^
+      20 | 
+      21 | it('fail with expected promise values and not', () =>
+      22 |   expect(Promise.resolve([1, 2])).resolves.not.toHaveLengthAsync(
 
-      at Object.toHaveLengthAsync (__tests__/failure.test.js:24:54)
-      at asyncGeneratorStep (__tests__/failure.test.js:11:103)
-      at _next (__tests__/failure.test.js:13:194)
-      at __tests__/failure.test.js:13:364
-      at Object.<anonymous> (__tests__/failure.test.js:13:97)
+      at Object.toHaveLengthAsync (__tests__/failure.test.js:19:41)
 
   ● fail with expected promise values and not
 
@@ -59,17 +73,13 @@ FAIL __tests__/failure.test.js
     received.length:
       2
 
-      28 | 
-      29 | it('fail with expected promise values and not', async () => {
-    > 30 |   await (expect(Promise.resolve([1, 2])).resolves.not: any).toHaveLengthAsync(
-         |                                                             ^
-      31 |     Promise.resolve(2)
-      32 |   );
-      33 | });
-
-      at Object.toHaveLengthAsync (__tests__/failure.test.js:30:61)
-      at asyncGeneratorStep (__tests__/failure.test.js:11:103)
-      at _next (__tests__/failure.test.js:13:194)
-      at __tests__/failure.test.js:13:364
-      at Object.<anonymous> (__tests__/failure.test.js:13:97)
+      20 | 
+      21 | it('fail with expected promise values and not', () =>
+    > 22 |   expect(Promise.resolve([1, 2])).resolves.not.toHaveLengthAsync(
+         |                                                ^
+      23 |     Promise.resolve(2)
+      24 |   ));
+      25 | 
+
+      at Object.toHaveLengthAsync (__tests__/failure.test.js:22:48)
 `;

e2e/__tests__/customMatcherStackTrace.test.js

@@ -12,7 +12,7 @@ import {extractSummary} from '../Utils';
 import {wrap} from 'jest-snapshot-serializer-raw';
 
 test('works with custom matchers', () => {
-  const {stderr} = runJest('custom-matcher-stack-trace');
+  const {stderr} = runJest('custom-matcher-stack-trace', ['sync.test.js']);
 
   let {rest} = extractSummary(stderr);
 
@@ -23,3 +23,13 @@ test('works with custom matchers', () => {
 
   expect(wrap(rest)).toMatchSnapshot();
 });
+
+test('custom async matchers', () => {
+  const {stderr} = runJest('custom-matcher-stack-trace', [
+    'asynchronous.test.js',
+  ]);
+
+  const {rest} = extractSummary(stderr);
+
+  expect(wrap(rest)).toMatchSnapshot();
+});

e2e/custom-matcher-stack-trace/__tests__/asynchronous.test.js

@@ -0,0 +1,18 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+expect.extend({toThrowCustomAsyncMatcherError});
+
+test('showing the stack trace for an async matcher', async () => {
+  await expect(true).toThrowCustomAsyncMatcherError();
+});
+
+async function toThrowCustomAsyncMatcherError() {
+  const message = () =>
+    'We expect the stack trace and code fence for this matcher to be shown in the console.';
+  return {message, pass: false};
+}

e2e/expect-async-matcher/__tests__/failure.test.js

@@ -4,30 +4,21 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
-'use strict';
 
 import {toHaveLengthAsync} from '../matchers';
 
-expect.extend({
-  toHaveLengthAsync,
-});
+expect.extend({toHaveLengthAsync});
 
-it('fail with expected non promise values', async () => {
-  await (expect([1]): any).toHaveLengthAsync(Promise.resolve(2));
-});
+it('fail with expected non promise values', () =>
+  expect([1]).toHaveLengthAsync(Promise.resolve(2)));
 
-it('fail with expected non promise values and not', async () => {
-  await (expect([1, 2]): any).not.toHaveLengthAsync(Promise.resolve(2));
-});
+it('fail with expected non promise values and not', () =>
+  expect([1, 2]).not.toHaveLengthAsync(Promise.resolve(2)));
 
-it('fail with expected promise values', async () => {
-  await (expect(Promise.resolve([1])): any).resolves.toHaveLengthAsync(
-    Promise.resolve(2)
-  );
-});
+it('fail with expected promise values', () =>
+  expect(Promise.resolve([1])).resolves.toHaveLengthAsync(Promise.resolve(2)));
 
-it('fail with expected promise values and not', async () => {
-  await (expect(Promise.resolve([1, 2])).resolves.not: any).toHaveLengthAsync(
+it('fail with expected promise values and not', () =>
+  expect(Promise.resolve([1, 2])).resolves.not.toHaveLengthAsync(
     Promise.resolve(2)
-  );
-});
+  ));

e2e/expect-async-matcher/__tests__/success.test.js

@@ -4,30 +4,21 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
-'use strict';
 
 import {toHaveLengthAsync} from '../matchers';
 
-expect.extend({
-  toHaveLengthAsync,
-});
+expect.extend({toHaveLengthAsync});
 
-it('works with expected non promise values', async () => {
-  await (expect([1]): any).toHaveLengthAsync(Promise.resolve(1));
-});
+it('works with expected non promise values', () =>
+  expect([1]).toHaveLengthAsync(Promise.resolve(1)));
 
-it('works with expected non promise values and not', async () => {
-  await (expect([1, 2]): any).not.toHaveLengthAsync(Promise.resolve(1));
-});
+it('works with expected non promise values and not', () =>
+  expect([1, 2]).not.toHaveLengthAsync(Promise.resolve(1)));
 
-it('works with expected promise values', async () => {
-  await (expect(Promise.resolve([1])).resolves: any).toHaveLengthAsync(
-    Promise.resolve(1)
-  );
-});
+it('works with expected promise values', () =>
+  expect(Promise.resolve([1])).resolves.toHaveLengthAsync(Promise.resolve(1)));
 
-it('works with expected promise values and not', async () => {
-  await (expect(Promise.resolve([1, 2])).resolves.not: any).toHaveLengthAsync(
+it('works with expected promise values and not', () =>
+  expect(Promise.resolve([1, 2])).resolves.not.toHaveLengthAsync(
     Promise.resolve(1)
-  );
-});
+  ));

packages/expect/src/index.js

@@ -251,7 +251,10 @@ const makeThrowingMatcher = (
       utils,
     };
 
-    const processResult = (result: SyncExpectationResult) => {
+    const processResult = (
+      result: SyncExpectationResult,
+      asyncError?: JestAssertionError,
+    ) => {
       _validateResult(result);
 
       getState().assertionCalls++;
@@ -264,6 +267,9 @@ const makeThrowingMatcher = (
         if (err) {
           error = err;
           error.message = message;
+        } else if (asyncError) {
+          error = asyncError;
+          error.message = message;
         } else {
           error = new JestAssertionError(message);
 
@@ -307,9 +313,13 @@ const makeThrowingMatcher = (
 
       if (isPromise((potentialResult: any))) {
         const asyncResult = ((potentialResult: any): AsyncExpectationResult);
+        const asyncError = new JestAssertionError();
+        if (Error.captureStackTrace) {
+          Error.captureStackTrace(asyncError, throwingMatcher);
+        }
 
         return asyncResult
-          .then(aResult => processResult(aResult))
+          .then(aResult => processResult(aResult, asyncError))
           .catch(error => handlError(error));
       } else {
         const syncResult = ((potentialResult: any): SyncExpectationResult);