@Test
public void resolve_strategyReturnsEmptyList_resolveReturnListIsEmpty() {

    // given
    ResolveStrategy strategy = mockStrategy();
    when(strategy.resolve(any(LookupContext.class))).thenReturn(Collections.<SagaInstanceInfo>emptyList());
    // when
    Collection<SagaInstanceInfo> instances = sut.resolve(null);
    // then
    assertThat("Expected an empty list.", instances, hasSize(0));
}