@Override
    public Set<String> getSupportedAnnotationTypes() {
      // for some reason annotation.getCanonicalName() is not found
      // using wildcard here
      return Collections.singleton("*");
    }
Flag to track if test statement was executed or not. Fail fast if annotation processor
was not triggered. IE detected false (no-op) test executions
processor-testlib/src/org/immutables/value/processor/meta/ProcessorRule.java