public static TestRunner of(SamzaApplication app) {
    Preconditions.checkNotNull(app);
    return new TestRunner(app);
  }
Creates an instance of {@link TestRunner} for a {@link SamzaApplication}
@param app a {@link SamzaApplication}
@return this {@link TestRunner}
samza-test/src/main/java/org/apache/samza/test/framework/TestRunner.java