@Test
public void testGetSrcLastModifiedMillis() {

    assertEquals(SAMPLE_LAST_MODIFIED_LONG, makeNormal().getSrcLastModifiedMillis());
    assertNull(makeEmpty().getSrcLastModifiedMillis());
    final B2Headers withBogusSrcLastModifiedMillis = B2HeadersImpl
            .builder()
            .set(B2Headers.SRC_LAST_MODIFIED_MILLIS, "non-numerical")
            .build();
    assertNull(withBogusSrcLastModifiedMillis.getSrcLastModifiedMillis());
}