private void mockBlobExistence(boolean exists) {
    when(mockBlockBlobAsyncClient.exists()).thenReturn(Mono.just(exists));
    if (exists) {
      BlobDownloadAsyncResponse response = mock(BlobDownloadAsyncResponse.class);
      byte[] randomBytes = TestUtils.getRandomBytes(blobSize);
      when(response.getValue()).thenReturn(Flux.just(ByteBuffer.wrap(randomBytes)));
      when(mockBlockBlobAsyncClient.downloadWithResponse(any(), any(), any(), anyBoolean())).thenReturn(
          Mono.just(response));
    } else {
      BlobStorageException ex = mockStorageException(BlobErrorCode.BLOB_NOT_FOUND);
      when(mockBlockBlobAsyncClient.downloadWithResponse(any(), any(), any(), anyBoolean())).thenReturn(Mono.error(ex));
    }
  }
Test findEntriesSince with entries having non unique updateTimes.
@throws Exception
ambry-cloud/src/test/java/com/github/ambry/cloud/azure/AzureCloudDestinationTest.java