Allure-playwright - Merged Report Timeline Shows Only One Shard & Time take is incorrect on overview

[gokultw]

Bug Report: Playwright Merged Report Timeline Shows Only One Shard

Describe the bug

When merging Playwright blob reports from multiple sharded test runs, the HTML report timeline only displays one shard's execution timeline instead of showing all shards' timelines. Additionally, the Overview tab shows incorrect start time, end time, and total duration.

To Reproduce

Steps to reproduce the behavior:

1. Configure Playwright with blob reporter for CI:

   // playwright.config.ts
   reporter: process.env.CI ? [['blob']] : reporters,

2. Run tests with sharding (e.g., 5 shards):

   npx playwright test --grep '@e2esanity' --shard=1/5
   npx playwright test --grep '@e2esanity' --shard=2/5
   npx playwright test --grep '@e2esanity' --shard=3/5
   npx playwright test --grep '@e2esanity' --shard=4/5
   npx playwright test --grep '@e2esanity' --shard=5/5

3. Merge the blob reports using merge.config.ts:

   npx playwright merge-reports --config merge.config.ts ./blob-reports

4. Open the merged HTML report:

   npx playwright show-report playwright-report

5. Navigate to the Timeline view

6. Check the Overview tab for start/end times and duration

7. Observe that only one shard's timeline is displayed and times are incorrect

Expected behavior

• The Timeline view should display execution timelines for all 5 shards running in parallel
• The Overview tab should show:
  • Start Time: Earliest start time across all shards
  • End Time: Latest end time across all shards
  • Duration: Time from earliest start to latest end (not sum of all shards)
• Should visualize parallel execution showing all shards running concurrently

Configuration Files

merge.config.ts

Documentation: https://playwright.dev/docs/test-sharding#merge-reports-cli

import { defineConfig } from '@playwright/test';
import { reporters } from './reporting.config';

/**
 * Configuration for merging blob reports from sharded test runs
 * See https://playwright.dev/docs/test-sharding#merge-reports-cli
 */
export default defineConfig({
  testDir: './tests',
  reporter: reporters,
});

reporting.config.ts

import * as env from '@env';
import type { ReporterDescription } from '@playwright/test';
import * as os from 'os';

/**
 * Centralized reporter configuration
 * Used by both playwright.config.ts (local) and merge.config.ts (CI merge)
 */
export const reporters: ReporterDescription[] = [
  ['html', { open: process.env.CI ? 'never' : 'always' }],
  ['line'],
  ...(process.env.CI
    ? [
        ['playwright-ctrf-json-reporter'] as ReporterDescription,
        ['./Utilities/badgeReporter.ts'] as ReporterDescription,
      ]
    : []),
  [
    'allure-playwright',
    {
      resultsDir: 'test-results/allure-results',
      detail: true,
      suiteTitle: true,
      environmentInfo: {
        Test_Environment: env.currentEnv,
        Locale: env.locale,
        Test_Tags: process.env.TEST_TAGS || '',
        Test_Suite: env.suiteName,
        Device: env.Device,
        os_platform: os.platform(),
        os_release: os.release(),
        os_version: os.version(),
        node_version: process.version,
      },
    },
  ],
];

playwright.config.ts (reporter section)

import { reporters } from './reporting.config';

export default defineConfig({
  // ... other config
  reporter: process.env.CI ? [['blob']] : reporters,
  // ... other config
});

Commands Used

Merge Command

npx playwright merge-reports --config merge.config.ts ./blob-reports

CI Workflow (GitHub Actions)

# Run sharded tests
- name: Run Playwright tests (Shard ${{ matrix.shard }})
  run: npx playwright test --grep '${{ inputs.testTags }}' --shard=${{ matrix.shard }}/${{ needs.calculate-shards.outputs.shard-count }}

# Upload blob reports
- name: Upload blob report
  uses: actions/upload-artifact@v4
  with:
    name: blob-report-${{ matrix.shard }}
    path: blob-report
    retention-days: 1

# Merge all blob reports
- name: Merge blob reports
  run: npx playwright merge-reports --config merge.config.ts ./all-blob-reports

Screenshots

• Timeline view displaying only one shard instead of all 5 shards

• Overview tab with incorrect start/end/duration times

• Expected: Timeline showing 5 parallel execution tracks

Environment

• OS: macOS (local) / Ubuntu (CI - GitHub Actions)
• Playwright Version: @playwright/test (latest)
• Node Version: LTS/*
• CI: GitHub Actions with self-hosted runners
• Sharding Configuration:
  • 5 parallel shards (dynamic based on test count)
  • 2 workers per shard
  • Total parallel capacity: 10 tests

Additional Context

• All 5 shards complete successfully and generate blob reports
• Individual shard blob reports are stored in ./blob-reports/blob-report-1 through ./blob-reports/blob-report-5
• Merged Allure report generates successfully but timeline/timing data appears incomplete or only shows one shard
• Expected behavior: Timeline should visualize parallel shard execution similar to how CI logs show parallel job execution

Related Documentation

• Playwright Test Sharding
• Merge Reports CLI
• Blob Reporter