Recognize typical assertion errors and use their formatting

lib/test.js

@@ -7,6 +7,16 @@ import concordanceOptions from './concordance-options.js';
 import nowAndTimers from './now-and-timers.cjs';
 import parseTestArgs from './parse-test-args.js';
 
+function isExternalAssertError(error) {
+	// Match errors thrown by <https://www.npmjs.com/package/expect>.
+	if (error.matcherResult) {
+		return true;
+	}
+
+	// Match errors thrown by <https://www.npmjs.com/package/chai> and <https://nodejs.org/api/assert.html>.
+	return error.hasOwnProperty('actual') && error.hasOwnProperty('expected');
+}
+
 function formatErrorValue(label, error) {
 	const formatted = concordance.format(error, concordanceOptions);
 	return {label, formatted};
@@ -519,11 +529,19 @@ export default class Test {
 
 		const result = this.callFn();
 		if (!result.ok) {
-			this.saveFirstError(new AssertionError({
-				message: 'Error thrown in test',
-				savedError: result.error instanceof Error && result.error,
-				values: [formatErrorValue('Error thrown in test:', result.error)],
-			}));
+			if (isExternalAssertError(result.error)) {
+				this.saveFirstError(new AssertionError({
+					message: 'Assertion failed',
+					savedError: result.error instanceof Error && result.error,
+					values: [{label: 'Assertion failed: ', formatted: result.error.message}]
+				}));
+			} else {
+				this.saveFirstError(new AssertionError({
+					message: 'Error thrown in test',
+					savedError: result.error instanceof Error && result.error,
+					values: [formatErrorValue('Error thrown in test:', result.error)]
+				}));
+			}
 
 			return this.finish();
 		}
@@ -564,11 +582,19 @@ export default class Test {
 
 				promise
 					.catch(error => {
-						this.saveFirstError(new AssertionError({
-							message: 'Rejected promise returned by test',
-							savedError: error instanceof Error && error,
-							values: [formatErrorValue('Rejected promise returned by test. Reason:', error)],
-						}));
+						if (isExternalAssertError(error)) {
+							this.saveFirstError(new AssertionError({
+								message: 'Assertion failed',
+								savedError: error instanceof Error && error,
+								values: [{label: 'Assertion failed: ', formatted: error.message}]
+							}));
+						} else {
+							this.saveFirstError(new AssertionError({
+								message: 'Rejected promise returned by test',
+								savedError: error instanceof Error && error,
+								values: [formatErrorValue('Rejected promise returned by test. Reason:', error)]
+							}));
+						}
 					})
 					.then(() => resolve(this.finish()));
 			});

test/external-assertions/fixtures/assert-failure.js

@@ -0,0 +1,7 @@
+import assert from 'node:assert';
+
+import test from 'ava';
+
+test('test', () => {
+	assert(false);
+});

test/external-assertions/fixtures/expect-failure.js

@@ -0,0 +1,7 @@
+import { expect } from 'expect';
+
+import test from 'ava';
+
+test('test', () => {
+	expect(false).toBeTruthy();
+});

test/external-assertions/fixtures/package.json

@@ -0,0 +1,11 @@
+{
+	"type": "module",
+	"ava": {
+		"files": [
+			"*.js"
+		]
+	},
+	"dependencies": {
+		"expect": "^29.5.0"
+	}
+}

test/external-assertions/snapshots/test.js.md

@@ -0,0 +1,60 @@
+# Snapshot report for `test/external-assertions/test.js`
+
+The actual snapshot is saved in `test.js.snap`.
+
+Generated by [AVA](https://avajs.dev).
+
+## node assertion
+
+> Snapshot 1
+
+    `␊
+      ✘ [fail]: test Assertion failed␊
+      ─␊
+    ␊
+      test␊
+    ␊
+      assert-failure.js:6␊
+    ␊
+       5: test('test', () => {␊
+       6:   assert(false);    ␊
+       7: });                 ␊
+    ␊
+      Assertion failed: ␊
+    ␊
+      false == true␊
+    ␊
+      › file://assert-failure.js:6:2␊
+    ␊
+      ─␊
+    ␊
+      1 test failed`
+
+## expect error
+
+> Snapshot 1
+
+    `␊
+      ✘ [fail]: test Assertion failed␊
+      ─␊
+    ␊
+      test␊
+    ␊
+      expect-failure.js:6␊
+    ␊
+       5: test('test', () => {         ␊
+       6:   expect(false).toBeTruthy();␊
+       7: });                          ␊
+    ␊
+      Assertion failed: ␊
+    ␊
+      expect(received).toBeTruthy()␊
+    ␊
+      Received: false␊
+    ␊
+      › Received: false␊
+      › file://expect-failure.js:6:16␊
+    ␊
+      ─␊
+    ␊
+      1 test failed`

test/external-assertions/test.js

@@ -0,0 +1,13 @@
+import test from '@ava/test';
+
+import {fixture} from '../helpers/exec.js';
+
+test('node assertion ', async t => {
+	const result = await t.throwsAsync(fixture(['assert-failure.js']));
+	t.snapshot(result.stdout);
+});
+
+test('expect error ', async t => {
+	const result = await t.throwsAsync(fixture(['expect-failure.js']));
+	t.snapshot(result.stdout);
+});