@Test
public void getKey_should_generate_serialized_key() throws Exception {

    // given
    final ContentCacheKey key = new TransformationMetadataCacheKey("prep1", "step1", HEAD, "user1");
    // when
    final String keyStr = key.getKey();
    // then
    assertThat(keyStr, is("transformation-metadata_prep1_step1_HEAD_user1"));
}