public void AddRange_ShouldSucceed_WithUnusedIds(string petId1, string name1, int fkAnimalTypeId1, string petId2, string name2, int fkAnimalTypeId2) { //Arrange Guid wrongGuid = Guid.Parse("c3b922ac-a2bf-4b75-a9dc-5b3c44798264"); Guid ownerGuid1 = Guid.Parse(petId1); Guid ownerGuid2 = Guid.Parse(petId2); _mockPetRepository.Setup(x => x.FindAsync(It.IsAny <Expression <Func <tblPet, bool> > >())) .ReturnsAsync(Enumerable.Empty <tblPet>()); tblPet owner1 = new tblPet() { Id = ownerGuid1, Name = name1, FKAnimalTypeId = fkAnimalTypeId1 }; tblPet owner2 = new tblPet() { Id = ownerGuid2, Name = name2, FKAnimalTypeId = fkAnimalTypeId2 }; var entities = new tblPet[] { owner1, owner2 }; //Act var result = _service.AddRange(entities); //Assert _mockPetRepository.Verify(x => x.FindAsync(It.IsAny <Expression <Func <tblPet, bool> > >()), Times.Once()); _mockPetRepository.Verify(x => x.AddRange(entities), Times.Once()); Assert.True(result.IsCompletedSuccessfully); }