@Test
  public void testNullStoreKeyConverter() throws IOException {
    try {
      new BlobIdTransformer(blobIdFactory, null);
      fail("Did not throw NullPointerException");
    } catch (NullPointerException e) {
      //expected
    }
  }
Tests creating the transformer with a null StoreKeyConverter
ambry-replication/src/test/java/com/github/ambry/replication/BlobIdTransformerTest.java