def test_self_referencing_interface(self):
class TreeNode(Interface):
pass
TreeNode.add_attribute('left', optional(TreeNode))
TreeNode.add_attribute('right', optional(TreeNode))
class TreeNodeImplementation:
def __init__(self):
self.left = None
self.right = None
tree = TreeNodeImplementation()
tree.left = TreeNodeImplementation()
tree.right = TreeNodeImplementation()
self.assertIsInstance(tree, TreeNode)
tree.left = 1
self.assertNotIsInstance(tree, TreeNode)
def test_optional(self):
self.assertIsInstance(1, optional(int))
self.assertIsInstance(None, optional(int))
self.assertNotIsInstance('string', optional(int))
def test(a: optional(int)):
return a
