@Before
  public void setup() {
    MockitoAnnotations.initMocks(this);
    addStreamMetadataCacheMetadata(this.streamMetadataCache,
        ImmutableMap.of(SYSTEM_STREAM0, buildSystemStreamMetadata(4), SYSTEM_STREAM1, buildSystemStreamMetadata(3)));
  }
Unfortunately, we still need powermock for testing the regex topic flow, since that flow checks for a specific
rewriter class, and setting up the support for that specific class is too cumbersome.
Many of the tests do not need powermock.
samza-core/src/test/java/org/apache/samza/coordinator/TestJobModelCalculator.java