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 details

• test-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

Coverage

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

• Jest --json reporter: https://jestjs.io/docs/cli#--json

• JUnit XML format specification: https://github.com/testmoapp/junitxml

• Istanbul coverage reporters: https://istanbul.js.org/docs/advanced/alternative-reporters/

• Allure Test Report framework: https://allurereport.org/

• GitHub Actions job summaries: https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#adding-a-job-summary