public void TestGetSubFolder() { //Arrange var parent = new Folder() { ID = 6, Name = "Folder6", IsRoot = true, SubFolders = new List <Folder>(), Files = new List <File>() }; var child1 = new Folder() { ID = 7, Name = "Folder7", ParentID = 6, Parent = parent, IsRoot = false, SubFolders = new List <Folder>(), Files = new List <File>() }; var child2 = new Folder() { ID = 8, Name = "Folder8", ParentID = 6, Parent = parent, IsRoot = false, SubFolders = new List <Folder>(), Files = new List <File>() }; //Act parent.SubFolders.Add(child1); parent.SubFolders.Add(child2); _folder.AddFolder(parent); _folder.AddFolder(child1); _folder.AddFolder(child2); //Convert both to list List <Folder> res1 = parent.SubFolders.ToList(); List <Folder> res2 = _folder.GetSubFolders(parent); //Assert - Use IsTrue because of object refrences Assert.AreEqual(res1.Count, res2.Count); }