StreamApplication getRepartitionOnlyStreamApplication() {
    return appDesc -> {
      MessageStream<KV<String, Object>> input1 = appDesc.getInputStream(input1Descriptor);
      input1.partitionBy(KV::getKey, KV::getValue, mock(KVSerde.class), "p1");
    };
  }
Unit test base class to set up commonly used test application and configuration.
samza-core/src/test/java/org/apache/samza/execution/ExecutionPlannerTestBase.java