def test_construction1(self):
a = Node('a')
assert a.name == 'a'
assert a.parents == []
assert a.children == []
assert a.is_root()
assert a.is_leaf()
def test_construction(self):
a = Node('a')
b = Node('b')
c = Node('c', b)
d = Node('d', a, c)
e = Node('e', d)
f = Node('f', d, c)
g = Node('g', e, f)
assert b.is_root()
assert c.parents == [b]
assert d.parents == [a, c]
assert g.parents == [e, f]
assert b.children == [c]
assert c.children == [d, f]
assert g.is_leaf()