fix: show stack traces on async assert errors

Fixes jestjs#6752

CHANGELOG.md

@@ -21,6 +21,7 @@
 - `[jest-snapshot]` Correctly merge property matchers with the rest of the snapshot in `toMatchSnapshot`. ([#6528](https://github.com/facebook/jest/pull/6528))
 - `[jest-snapshot]` Add error messages for invalid property matchers. ([#6528](https://github.com/facebook/jest/pull/6528))
 - `[jest-cli]` Show open handles from inside test files as well ([#6263](https://github.com/facebook/jest/pull/6263))
+- `[jest-jasmine]` Show proper error message from async `assert` errors
 
 ### Chore & Maintenance
 

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

@@ -456,6 +456,7 @@ exports[`works with node assert 1`] = `
  ✕ assert.ifError
  ✕ assert.doesNotThrow
  ✕ assert.throws
+ ✕ async
 
  ● assert
 
@@ -809,9 +810,43 @@ exports[`works with node assert 1`] = `
  | ^
  78 | });
  79 | 
+ 80 | test('async', async () => {
 
  at __tests__/node_assertion_error.test.js:77:10
 
+ ● async
+
+ Failed: \\"assert.equal(received, expected) or assert(received) 
+
+ Expected value to be equal to:
+ \\\\\\"hello\\\\\\"
+ Received:
+ \\\\\\"hello
+ goodbye\\\\\\"
+
+ Message:
+ hmmm
+
+ Difference:
+
+ - Expected
+ + Received
+
+ hello
+ + goodbye
+
+ 79 | 
+ 80 | test('async', async () => {
+ > 81 | assert.equal('hello\\\\ngoodbye', 'hello', 'hmmm');
+ | ^
+ 82 | });
+ 83 | 
+
+ at __tests__/node_assertion_error.test.js:81:10
+ at __tests__/node_assertion_error.test.js:12:191
+ at __tests__/node_assertion_error.test.js:12:437
+ at __tests__/node_assertion_error.test.js:12:99
+
 "
 `;
 

e2e/failures/__tests__/node_assertion_error.test.js

@@ -76,3 +76,7 @@ test('assert.doesNotThrow', () => {
 test('assert.throws', () => {
  assert.throws(() => {});
 });
+
+test('async', async () => {
+ assert.equal('hello\ngoodbye', 'hello', 'hmmm');
+});

packages/jest-jasmine2/src/jasmine/Env.js

@@ -30,9 +30,11 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 /* eslint-disable sort-keys */
 
+import {AssertionError} from 'assert';
 import queueRunner from '../queue_runner';
 import treeProcessor from '../tree_processor';
 import checkIsError from '../is_error';
+import assertionErrorMessage from '../assert_support';
 
 // Try getting the real promise object from the context, if available. Someone
 // could have overridden it in a test. Async functions return it implicitly.
@@ -547,6 +549,10 @@ export default function(j$) {
  };
 
  this.fail = function(error) {
+ if (error instanceof AssertionError) {
+ error = assertionErrorMessage(error, {expand: j$.Spec.expand});
+ }
+
  const {isError, message} = checkIsError(error);
 
  currentRunnable().addExpectationResult(false, {