public void ShouldTraverseTreeInOrder_WhenTraverseOrderIsInOrder() { //When var items = _tree.Traverse(TraverseOrder.InOrder); //Then Assert.Collection(items, i => Assert.Equal(3, i), i => Assert.Equal(5, i), i => Assert.Equal(9, i), i => Assert.Equal(10, i), i => Assert.Equal(20, i), i => Assert.Equal(25, i) ); }