[Test] public async Task GetAgencyRegions_Always_Should_FilterRegionsByAgencyId() { // Arrange var agencyId1 = Guid.NewGuid(); var agencyId2 = Guid.NewGuid(); var regionName1 = "Region 1"; var regionName2 = "Region "; _efContext.Agency.Add(new Agency { Id = agencyId1, GlobalAgencyRegion = new GlobalAgencyRegion { Id = Guid.NewGuid(), Region = regionName1, GlobalAgency = new GlobalAgency() } }); _efContext.Agency.Add(new Agency { Id = agencyId2, GlobalAgencyRegion = new GlobalAgencyRegion { Id = Guid.NewGuid(), Region = regionName2, GlobalAgency = new GlobalAgency() } }); _efContext.SaveChanges(); // Act await _regionsService.GetAgencyRegions(agencyId1); // Assert _mapperMock.Verify(m => m.Map <IEnumerable <RegionModel> >(It.Is <IEnumerable <GlobalAgencyRegion> >(i => i.Count(gar => gar.Region == regionName1) == 1)), Times.Once); }