e2e retry blog post - merge JUnit test results script

run_tests_with_retries.js

async function runTestsAndRetry(jestConfig, retriesRemaining, mergedResults) {
  const { results } = await runCLI(jestConfig, ['e2e/test']);
  
  mergedResults = mergeTestResults(mergedResults, results);
  
  // configure jest-junit for our test run
  const junit = new JestJunit(
    {},
    {
      outputDirectory: './test-results/',
      outputName: 'jest-puppeteer.xml',
    }
  );
  junit.onRunComplete(null, mergedResults);

  // ...

  return await runTestsAndRetry(jestConfig, retriesRemaining, mergedResults);
}

function mergeTestResults(oldResults, newResults) {
  // if it's the first run, we can just return the results
  if (!oldResults.testResults) {
    return newResults;
  }

  // make a copy of the old results so we don't mutate the input
  const mergedResults = JSON.parse(JSON.stringify(oldResults));

  // for each new result, input it in the old results alongside
  // the previous result for that test
  newResults.testResults.forEach((newResult) => {
    const oldResultIdx = mergedResults.testResults.findIndex(
      (result) => result.testFilePath === newResult.testFilePath
    );
    mergedResults.testResults.splice(oldResultIdx, 0, newResult);
  });
 
  return mergedResults;
}