@AfterClass
  public static void explainGoldenFileFailures() {
    if (goldenFileFailures) {
      System.err.println();
      System.err.println("Some golden-file tests failed.");
    }
  }
Config that is used for negative tests, and to update the golden files. Since those files use
{@code javax.inject}, we need a config that specifies that package.
factory/src/test/java/com/google/auto/factory/processor/AutoFactoryProcessorTest.java