public async Task DeleteByProduct_ShouldOk() { var mock = new Mock <IReviewService>(MockBehavior.Strict); mock.Setup(repo => repo.DeleteReviewByProductAsync(1, "")).Returns(Task.Run(() => { })).Verifiable(); var controller = new ReviewController(mock.Object); var result = await controller.DeleteByProduct(1); var controllerResult = result as OkResult; Assert.IsNotNull(controllerResult); mock.Verify(); mock.Verify(repo => repo.DeleteReviewByProductAsync(1, ""), Times.Once); }