public void ShouldReturnAllPostsWhenNoDateRangeIsEntered() { _postDataAccess = new Mock<IPostDataAccess>(); _postDataAccess.Setup(x => x.GetPostsByDateRange(It.IsAny<DateTime>(), It.IsAny<DateTime>())) .Returns(Mother.PostsWithoutTagsOrComments); var sut = new PostBLL(_postDataAccess.Object); var posts = sut.GetPostsByDateRange(null, null); Assert.Equal(Mother.PostsWithoutTagsOrComments.Count(), posts.Count()); }