Test Report Generator
Overview
Generate structured, human-readable test reports from raw test runner output including JUnit XML, Jest JSON, pytest results, and coverage data. Produces Markdown summaries, HTML dashboards, and CI-compatible annotations.
Prerequisites
- Test results in a parseable format (JUnit XML, Jest
--json, pytest --junitxml, or TAP)
- Coverage data files (Istanbul
coverage-summary.json, lcov.info, or coverage.xml)
- Node.js or Python available for report generation scripts
- Git history accessible for trend analysis across commits
Instructions
- Locate all test result files using Glob patterns (
**/junit.xml, **/test-results.json, **/coverage/lcov.info).
- Parse each result file and extract:
- Total test count, passed, failed, skipped, and error counts.
- Execution duration per test suite and per individual test.
- Failure messages, stack traces, and assertion details.
- Parse coverage data and extract:
- Line, branch, function, and statement coverage percentages.
- Per-file coverage breakdown identifying files below threshold.
- Uncovered line ranges for targeted improvement.
- Compute aggregate metrics:
- Overall pass rate as a percentage.
- Total execution time and average test duration.
- Top 10 slowest tests with file paths and durations.
- Coverage delta compared to the previous commit (if git history is available).
- Generate a Markdown report with sections for summary, failures, coverage, and performance.
- Optionally generate an HTML report with sortable tables and coverage heatmaps.
- Write CI-compatible output (GitHub Actions job summary, GitLab report artifacts, or Slack webhook payload).
Output
test-report.md -- Markdown summary with pass/fail table, coverage stats, and failure detailstest-report.html -- Self-contained HTML report (optional)- Coverage summary table with per-file breakdown and delta from baseline
- Slowest tests list ranked by execution time
- CI annotation comments on failed test lines (GitHub Actions
::error format)
Error Handling
| Error |
Cause |
Solution |
| No test result files found |
Tests did not run or output path is incorrect |
Verify test runner --outputFile or --junitxml flag; check the output directory exists |
| Malformed JUnit XML |
Test runner crashed mid-output or encoding issues |
Validate XML with xmllint; re-run failed test suite; check for binary output in XML |
| Coverage data missing |
Tests ran without --coverage flag |
Add --coverage to the test command; verify coverage reporter is configured |
| Metric trend unavailable |
No previous report to compare against |
Generate baseline report first; store reports as CI artifacts for historical comparison |
| Report exceeds GitHub comment limit |
Too many failures produce oversized Markdown |
Truncate failure details to top 20; link to full report artifact |
Examples
Markdown report structure:
## Test Results -- 2026-03-10
| Metric | Value |
|--------|-------|
| Total Tests | 847 | # 847 = configured value
| Passed | 839 (99.1%) | # 839 = configured value
| Failed | 5 |
| Skipped | 3 |
| Duration | 42.3s |
### Coverage
| Category | Current | Threshold | Status |
|----------|---------|-----------|--------|
| Lines | 87.2% | 80% | PASS |
| Branches | 74.1% | 70% | PASS |
| Functions | 91.5% | 85% | PASS |
### Failed Tests
1. `src/utils/parser.test.ts` -- "handles malformed input" -- Expected Error but received null
2. `src/api/auth.test.ts` -- "rejects expired tokens" -- Timeout after 5000ms
GitHub Actions job summary integration:
cat test-report.md >> "$GITHUB_STEP_SUMMARY"
Resources
1---2name: generating-test-reports3description: Generate comprehensive test reports with metrics, coverage, and visualizations. Use when performing specialized testing. Trigger with phrases like "generate test report", "create test documentation", or "show test metrics".4license: MIT5---6# Test Report Generator78## Overview910Generate structured, human-readable test reports from raw test runner output including JUnit XML, Jest JSON, pytest results, and coverage data. Produces Markdown summaries, HTML dashboards, and CI-compatible annotations.1112## Prerequisites1314- Test results in a parseable format (JUnit XML, Jest `--json`, pytest `--junitxml`, or TAP)15- Coverage data files (Istanbul `coverage-summary.json`, `lcov.info`, or `coverage.xml`)16- Node.js or Python available for report generation scripts17- Git history accessible for trend analysis across commits1819## Instructions20211. Locate all test result files using Glob patterns (`**/junit.xml`, `**/test-results.json`, `**/coverage/lcov.info`).222. Parse each result file and extract:23 - Total test count, passed, failed, skipped, and error counts.24 - Execution duration per test suite and per individual test.25 - Failure messages, stack traces, and assertion details.263. Parse coverage data and extract:27 - Line, branch, function, and statement coverage percentages.28 - Per-file coverage breakdown identifying files below threshold.29 - Uncovered line ranges for targeted improvement.304. Compute aggregate metrics:31 - Overall pass rate as a percentage.32 - Total execution time and average test duration.33 - Top 10 slowest tests with file paths and durations.34 - Coverage delta compared to the previous commit (if git history is available).355. Generate a Markdown report with sections for summary, failures, coverage, and performance.366. Optionally generate an HTML report with sortable tables and coverage heatmaps.377. Write CI-compatible output (GitHub Actions job summary, GitLab report artifacts, or Slack webhook payload).3839## Output4041- `test-report.md` -- Markdown summary with pass/fail table, coverage stats, and failure details42- `test-report.html` -- Self-contained HTML report (optional)43- Coverage summary table with per-file breakdown and delta from baseline44- Slowest tests list ranked by execution time45- CI annotation comments on failed test lines (GitHub Actions `::error` format)4647## Error Handling4849| Error | Cause | Solution |50|-------|-------|---------|51| No test result files found | Tests did not run or output path is incorrect | Verify test runner `--outputFile` or `--junitxml` flag; check the output directory exists |52| Malformed JUnit XML | Test runner crashed mid-output or encoding issues | Validate XML with `xmllint`; re-run failed test suite; check for binary output in XML |53| Coverage data missing | Tests ran without `--coverage` flag | Add `--coverage` to the test command; verify coverage reporter is configured |54| Metric trend unavailable | No previous report to compare against | Generate baseline report first; store reports as CI artifacts for historical comparison |55| Report exceeds GitHub comment limit | Too many failures produce oversized Markdown | Truncate failure details to top 20; link to full report artifact |5657## Examples5859**Markdown report structure:**60```markdown61## Test Results -- 2026-03-106263| Metric | Value |64|--------|-------|65| Total Tests | 847 | # 847 = configured value66| Passed | 839 (99.1%) | # 839 = configured value67| Failed | 5 |68| Skipped | 3 |69| Duration | 42.3s |7071### Coverage72| Category | Current | Threshold | Status |73|----------|---------|-----------|--------|74| Lines | 87.2% | 80% | PASS |75| Branches | 74.1% | 70% | PASS |76| Functions | 91.5% | 85% | PASS |7778### Failed Tests791. `src/utils/parser.test.ts` -- "handles malformed input" -- Expected Error but received null802. `src/api/auth.test.ts` -- "rejects expired tokens" -- Timeout after 5000ms81```8283**GitHub Actions job summary integration:**84```bash85cat test-report.md >> "$GITHUB_STEP_SUMMARY"86```8788## Resources8990- Jest `--json` reporter: https://jestjs.io/docs/cli#--json91- JUnit XML format specification: https://github.com/testmoapp/junitxml92- Istanbul coverage reporters: https://istanbul.js.org/docs/advanced/alternative-reporters/93- Allure Test Report framework: https://allurereport.org/94- GitHub Actions job summaries: https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#adding-a-job-summary
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