Fix custom async matcher stack traces

CHANGELOG.md

@@ -116,6 +116,7 @@
 - `[jest-config]` Normalize `config.cwd` and `config.rootDir` using `realpath ([#7598](https://github.com/facebook/jest/pull/7598))
 - `[jest-environment-node]` Fix buffer property is not ArrayBuffer issue. ([#7626](https://github.com/facebook/jest/pull/7626))
 - `[babel-plugin-jest-hoist]` Ignore TS type annotations when looking for out-of-scope references ([#7641](https://github.com/facebook/jest/pull/7641))
+- `[expect]` Fix custom async matcher stack trace ([#7652](https://github.com/facebook/jest/pull/7652))
 
 ### Chore & Maintenance
 

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

@@ -1,12 +1,51 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`custom async matchers 1`] = `
+Object {
+  "rest": "FAIL __tests__/async.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.
+
+      2 | 
+      3 | test('showing the stack trace for an async matcher', async () => {
+    > 4 |   await expect(true).toThrowCustomAsyncMatcherError();
+        |                      ^
+      5 | });
+      6 | 
+      7 | async function toThrowCustomAsyncMatcherError() {
+
+      at Object.toThrowCustomAsyncMatcherError (__tests__/async.test.js:4:22)
+
+",
+  "summary": "Test Suites: 1 failed, 1 total
+Tests:       1 failed, 1 total
+Snapshots:   0 total
+Time:        <<REPLACED>>
+Ran all test suites matching /async.test.js/i.
+",
+}
+`;
+
 exports[`works with custom matchers 1`] = `
-"FAIL __tests__/customMatcher.test.js
-  Custom matcher
-    ✓ passes
-    ✓ fails
-    ✕ preserves error stack
+"FAIL __tests__/async.test.js
+  ● 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.
+
+      2 | 
+      3 | test('showing the stack trace for an async matcher', async () => {
+    > 4 |   await expect(true).toThrowCustomAsyncMatcherError();
+        |                      ^
+      5 | });
+      6 | 
+      7 | async function toThrowCustomAsyncMatcherError() {
+
+      at Object.toThrowCustomAsyncMatcherError (__tests__/async.test.js:4:22)
 
+FAIL __tests__/sync.test.js
   ● Custom matcher › preserves error stack
 
     qux
@@ -19,12 +58,12 @@ exports[`works with custom matchers 1`] = `
       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__/customMatcherStackTrace.test.js

@@ -12,7 +12,7 @@ import runJest from '../runJest';
 import {extractSummary} from '../Utils';
 
 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 +23,11 @@ test('works with custom matchers', () => {
 
   expect(rest).toMatchSnapshot();
 });
+
+test('custom async matchers', () => {
+  const {stderr} = runJest('custom-matcher-stack-trace', ['async.test.js']);
+
+  const result = extractSummary(stderr);
+
+  expect(result).toMatchSnapshot();
+});

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

@@ -0,0 +1,11 @@
+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};
+}

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);