public void UnionLayoutList() { LayoutInfo layout1 = new LayoutInfo() { Id = "vlarf" }; LayoutInfo layout2 = new LayoutInfo() { Id = "test" }; LayoutInfo layout3 = new LayoutInfo() { Id = "today" }; LayoutList list1 = new LayoutList(); list1.Add(layout1); list1.Add(layout2); LayoutList list2 = new LayoutList(); list2.Add(layout1); list2.Add(layout3); var union = list1.AsEnumerable().Union(list2.AsEnumerable()); Assert.NotNull(union); }