function defineSnapshotTestFromFixture(dirName, module, options, testFilePrefix, testName, testOptions = {}) {
  const extension = extensionForParser(testOptions.parser || module.parser)
  const fixtureDir = path.join(dirName, '..', '__testfixtures__');
  const inputPath = path.join(fixtureDir, testFilePrefix + `.input.${extension}`);
  const source = fs.readFileSync(inputPath, 'utf8');
  const testResult = defineSnapshotTest(module, options, source, testName)
  return testResult instanceof Promise ? testResult : undefined;
}
Handles file-loading boilerplates, using same defaults as defineTest