def testLoop(self):
# No Loops
input1 = Tree(children=TreeTest.tree_layout)
input2 = Tree(children=TreeTest.tree_layout_2)
input3 = Tree(children=TreeTest.tree_layout_3)
self.assertFalse(input1.has_loop())
self.assertFalse(input2.has_loop())
self.assertFalse(input3.has_loop())
input1.append(input2)
self.assertFalse(input1.has_loop())
# Loops
input2.append(input1)
input1.append(input2)
self.assertTrue(input1.has_loop())
input4 = Tree(children=TreeTest.tree_layout)
input5 = Tree(children=TreeTest.tree_layout_2)
input6 = Tree(children=TreeTest.tree_layout_3)
input6.append(input4)
input4.append(input5)
input5.append(input6)
self.assertTrue(input4.has_loop())
self.assertTrue(input5.has_loop())
self.assertTrue(input6.has_loop())
