Add invert tree challenge

graphs_trees/invert_tree/test_invert_tree.py

@@ -0,0 +1,32 @@
+from nose.tools import assert_equal, assert_raises
+
+
+class TestInvertTree(object):
+
+    def test_invert_tree(self):
+        root = Node(5)
+        bst = InverseBst(root)
+        node2 = bst.insert(2)
+        node3 = bst.insert(3)
+        node1 = bst.insert(1)
+        node7 = bst.insert(7)
+        node6 = bst.insert(6)
+        node9 = bst.insert(9)
+        result = bst.invert_tree()
+        assert_equal(result, root)
+        assert_equal(result.left, node7)
+        assert_equal(result.right, node2)
+        assert_equal(result.left.left, node9)
+        assert_equal(result.left.right, node6)
+        assert_equal(result.right.left, node3)
+        assert_equal(result.right.right, node1)
+        print('Success: test_invert_tree')
+
+
+def main():
+    test = TestInvertTree()
+    test.test_invert_tree()
+
+
+if __name__ == '__main__':
+    main()