Function transformFixture

compiler/packages/snap/src/runner-worker.ts:166–238

(
  fixture: TestFixture,
  compilerVersion: number,
  shouldLog: boolean,
  includeEvaluator: boolean,
)

}

export async function transformFixture(
  fixture: TestFixture,
  compilerVersion: number,
  shouldLog: boolean,
  includeEvaluator: boolean,
): Promise<TestResult> {
  const {input, snapshot: expected, snapshotPath: outputPath} = fixture;
  const basename = getBasename(fixture);
  const expectError = isExpectError(fixture);

  // Input will be null if the input file did not exist, in which case the output file
  // is stale
  if (input === null) {
    return {
      outputPath,
      actual: null,
      expected,
      unexpectedError: null,
    };
  }
  const {compileResult, error} = await compile(
    input,
    fixture.fixturePath,
    compilerVersion,
    shouldLog,
    includeEvaluator,
  );

  let unexpectedError: string | null = null;
  if (expectError) {
    if (error === null) {
      unexpectedError = `Expected an error to be thrown for fixture: \`${basename}\`, remove the 'error.' prefix if an error is not expected.`;
    }
  } else {
    if (error !== null) {
      unexpectedError = `Expected fixture \`${basename}\` to succeed but it failed with error:\n\n${error}`;
    } else if (compileResult == null) {
      unexpectedError = `Expected output for fixture \`${basename}\`.`;
    }
  }

  const snapOutput: string | null = compileResult?.forgetOutput ?? null;
  let sproutOutput: string | null = null;
  if (compileResult?.evaluatorCode != null) {
    const sproutResult = runSprout(
      compileResult.evaluatorCode.original,
      compileResult.evaluatorCode.forget,
    );
    if (sproutResult.kind === 'invalid') {
      unexpectedError ??= '';
      unexpectedError += `\n\n${sproutResult.value}`;
    } else {
      sproutOutput = sproutResult.value;
    }
  } else if (!includeEvaluator && expected != null) {
    sproutOutput = expected.split('\n### Eval output\n')[1];
  }