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dimazollo wants to merge 2 commits into from
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fix(playwright): recognize modern screenshot comparison errors #2

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362d75e
fix(playwright): recognize modern screenshot comparison errors
dimazollo Sep 7, 2026
edb83a5
test(playwright): make screenshot attachments explicit
dimazollo Sep 7, 2026
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23 changes: 22 additions & 1 deletion lib/adapters/test-result/playwright.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -212,7 +212,7 @@ export class PlaywrightTestResultAdapter implements ReporterTestResult {

if (/snapshot .*doesn't exist/.test(message) && message.includes('.png')) {
result.name = ErrorName.NO_REF_IMAGE;
} else if (message.includes('Screenshot comparison failed')) {
} else if (this._testResult.errors.every(error => this._isScreenshotComparisonError(error))) {
result.name = ErrorName.IMAGE_DIFF;
}

Expand Down Expand Up @@ -368,6 +368,27 @@ export class PlaywrightTestResultAdapter implements ReporterTestResult {
return _.groupBy(imageAttachments, a => a.name.replace(ANY_IMAGE_ENDING_REGEXP, ''));
}

private _isScreenshotComparisonError(error: PlaywrightTestResult['errors'][number]): boolean {
const message = stripAnsi(error.message || '');
const header = message.split('\n')[0];
if (header.includes('Screenshot comparison failed')) {
return true;
}

if (!/^(?:Error: )?expect\((?:page|locator|Buffer)\)\.(?:toHaveScreenshot|toMatchSnapshot)\(expected\)(?: failed)?$/.test(header)) {
return false;
}

// Modern Playwright uses the same matcher header for diffs and capture errors.
const snapshotName = message.match(/^\s*Snapshot: (.+)\.png\s*$/m)?.[1];
const states = Object.entries(this._attachmentsByState).filter(([state]) =>
snapshotName ? state === snapshotName : this._testResult.errors.length === 1);

return states.some(([, attachments]) =>
[ImageTitleEnding.Expected, ImageTitleEnding.Actual, ImageTitleEnding.Diff].every(ending =>
attachments.some(attachment => attachment.name.endsWith(ending))));
}

get duration(): number {
return this._testResult.duration;
}
Expand Down
103 changes: 103 additions & 0 deletions test/unit/lib/adapters/test-result/playwright.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -115,6 +115,109 @@ describe('PlaywrightTestResultAdapter', () => {
assert.strictEqual(error?.stack, errorStack);
});

['locator', 'page', 'Buffer'].forEach(receiver => {
it(`should recognize modern ${receiver} screenshot diffs`, () => {
const matcher = receiver === 'Buffer' ? 'toMatchSnapshot' : 'toHaveScreenshot';
const suffix = receiver === 'Buffer' ? '' : ' failed';
const errors = [{message: `Error: expect(${receiver}).${matcher}(expected)${suffix}\n\n Snapshot: state1.png`}];
const attachments = [
createAttachment('state1-expected.png'),
createAttachment('state1-diff.png'),
createAttachment('state1-actual.png')
];
const adapter = new PlaywrightTestResultAdapter(mkTestCase(), mkTestResult({errors, attachments}), UNKNOWN_ATTEMPT);

assert.equal(adapter.error?.name, ErrorName.IMAGE_DIFF);
assert.equal(adapter.status, FAIL);
});
});

['Screenshot comparison failed', 'Error: expect(page).toHaveScreenshot(expected) failed'].forEach(message => {
it(`should preserve other failures alongside "${message}"`, () => {
const errors = [{message}, {message: 'Error: expect(received).toBe(expected)'}];
const attachments = [
createAttachment('state1-expected.png'),
createAttachment('state1-diff.png'),
createAttachment('state1-actual.png')
];
const adapter = new PlaywrightTestResultAdapter(mkTestCase(), mkTestResult({errors, attachments}), UNKNOWN_ATTEMPT);

assert.equal(adapter.error?.name, ErrorName.GENERAL_ERROR);
assert.equal(adapter.status, ERROR);
});
});

it('should not treat screenshot capture failures as acceptable diffs', () => {
const errors = [{message: 'Error: expect(locator).toHaveScreenshot(expected) failed\n\n Snapshot: state1.png'}];
const attachments = [createAttachment('state1-actual.png'), createAttachment('state1-previous.png')];
const adapter = new PlaywrightTestResultAdapter(mkTestCase(), mkTestResult({errors, attachments}), UNKNOWN_ATTEMPT);

assert.equal(adapter.error?.name, ErrorName.GENERAL_ERROR);
assert.equal(adapter.status, ERROR);
});

it('should match diff attachments to the failing snapshot', () => {
const errors = [{message: 'Error: expect(locator).toHaveScreenshot(expected) failed\n\n Snapshot: state2.png'}];
const attachments = [
createAttachment('state1-expected.png'),
createAttachment('state1-diff.png'),
createAttachment('state1-actual.png')
];
const adapter = new PlaywrightTestResultAdapter(mkTestCase(), mkTestResult({errors, attachments}), UNKNOWN_ATTEMPT);

assert.equal(adapter.error?.name, ErrorName.GENERAL_ERROR);
});

it('should recognize an unnamed modern screenshot diff', () => {
const errors = [{message: 'Error: expect(page).toHaveScreenshot(expected) failed'}];
const attachments = [
createAttachment('state1-expected.png'),
createAttachment('state1-diff.png'),
createAttachment('state1-actual.png')
];
const adapter = new PlaywrightTestResultAdapter(mkTestCase(), mkTestResult({errors, attachments}), UNKNOWN_ATTEMPT);

assert.equal(adapter.error?.name, ErrorName.IMAGE_DIFF);
});

it('should recognize modern screenshot diffs with ANSI formatting', () => {
const errors = [{message: 'Error: \u001b[31mexpect(page).toHaveScreenshot(expected)\u001b[39m failed\n\n Snapshot: state1.png'}];
const attachments = [
createAttachment('state1-expected.png'),
createAttachment('state1-diff.png'),
createAttachment('state1-actual.png')
];
const adapter = new PlaywrightTestResultAdapter(mkTestCase(), mkTestResult({errors, attachments}), UNKNOWN_ATTEMPT);

assert.equal(adapter.error?.name, ErrorName.IMAGE_DIFF);
});

it('should recognize multiple named soft screenshot diffs', () => {
const errors = ['state1', 'state2'].map(state => ({
message: `Error: expect(locator).toHaveScreenshot(expected) failed\n\n Snapshot: ${state}.png`
}));
const attachments = ['state1', 'state2'].flatMap(state =>
[ImageTitleEnding.Expected, ImageTitleEnding.Actual, ImageTitleEnding.Diff].map(ending => createAttachment(state + ending)));
const adapter = new PlaywrightTestResultAdapter(mkTestCase(), mkTestResult({errors, attachments}), UNKNOWN_ATTEMPT);

assert.equal(adapter.error?.name, ErrorName.IMAGE_DIFF);
});

it('should not associate an unnamed capture error with another soft assertion diff', () => {
const errors = [
{message: 'Error: expect(page).toHaveScreenshot(expected) failed\n\n Snapshot: state1.png'},
{message: 'Error: expect(locator).toHaveScreenshot(expected) failed'}
];
const attachments = [
createAttachment('state1-expected.png'),
createAttachment('state1-diff.png'),
createAttachment('state1-actual.png')
];
const adapter = new PlaywrightTestResultAdapter(mkTestCase(), mkTestResult({errors, attachments}), UNKNOWN_ATTEMPT);

assert.equal(adapter.error?.name, ErrorName.GENERAL_ERROR);
});

it('should convert multiple errors to a single JSON string', () => {
const errors = [
{message: 'First error', stack: 'Error: First error at some-file.ts:5:10'},
Expand Down