public async Task ArticleDetailsAsync() { // Arrange this.context.Articles.Add(new Article { Id = 1, Title = "First article" }); await this.context.SaveChangesAsync(); this.blogRepositoryMock .Setup(x => x.Details()) .Returns(this.context.Articles) .Verifiable(); var service = new BlogArticleService(this.blogRepositoryMock.Object, this.mapper); // Act var result = service.ArticleDetailsAsync <ArticleDetailsViewModel>(1); // Assert Assert.NotNull(result); await Assert.IsAssignableFrom <Task <ArticleDetailsViewModel> >(result); Assert.Equal(1, result.Id); Assert.Equal("First article", result.Result.Title); }