static File fileForClass(String className) {
      Class<?> c;
      try {
        c = Class.forName(className);
      } catch (ClassNotFoundException e) {
        throw new IllegalArgumentException(e);
      }
      URL url = c.getProtectionDomain().getCodeSource().getLocation();
      assertThat(url.getProtocol()).isEqualTo("file");
      return new File(url.getPath());
    }
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