def test_node_add_child():
n1 = Node("Node1")
n2 = Node("Node2")
n3 = Node("Node3")
n1.add_child(n2)
n1.add_child(n3)
n2.add_child(n3)
## check n1 prperties.
assert (n2 in n1.children) and (n3 in n1.children)
assert n1.parents == []
## check n2 properties
assert (n1 in n2.parents) and (n3 in n2.children)
## checck n3 properties
assert (n2 in n3.parents) and (n1 in n3.parents)
assert n3.children == []
def test_node_search():
n1 = Node("Node1")
n2 = Node("Node2")
n3 = Node("Node3")
n4 = Node("Node4")
n1.add_child(n2)
n1.add_child(n3)
n2.add_child(n4)
assert (None != n1.search("Node2"))
assert (None != n1.search("Node3"))
assert (None != n1.search("Node4"))
assert (None == n1.search("Node42"))
assert (None != n2.search("Node4"))
assert (None == n2.search("Node3"))
assert (None == n3.search("Node1"))
assert (None == n3.search("Node2"))
assert (None == n3.search("Node4"))
assert (None == n4.search("Node1"))
assert (None == n4.search("Node2"))
assert (None == n4.search("Node3"))
assert (None != n4.search("Node4"))
def test_node_constructor():
n1 = Node("Name1")
assert n1.name == "Name1"
assert n1.parents == []
assert n1.children == []
