public async void GetAllOptionByProductIdAsync_ShouldReturnOptions() { // Arrange var resultExpected = new List <ProductOption>() { new ProductOption() { Name = "option1" }, new ProductOption() { Name = "option2" } }; var productId = Guid.NewGuid(); OptionRepositoryMock.Setup(x => x.GetAllOptionByProductIdAsync(productId)).ReturnsAsync(resultExpected); // Act var result = await ServiceTest.GetAllOptionByProductIdAsync(productId); // Assert Assert.Equal(resultExpected, result); }