def test_Key_shift():
# because the Key class preserves the key captured at object
# instantiation you have to deliberately tamper with the Key's value
# to make it equal to the shifted Node
key = Key('A|B')
key.value = Node(head='B', tail=[])
assert (Key('A|B') << 1) == key
key.value = Node(head=None, tail=[])
assert (Key('A|B') << 2) == key
def test_Key_Node_from_key():
assert Key.Node_from_key('A|B|C') == Node(head='A', tail=['B', ['C']])
def test_Node_from_nested_list():
# e.g. split from key:
# 'A|B|C' -> ['A', '|', 'B', '|', 'C'] -> ['A', ['B', ['C']]]
ll = ['A', ['B', ['C']]]
assert Node.from_nested_list(ll) == Node(head='A', tail=['B', ['C']])
def test_Key():
key = Key()
assert key.key is None
assert key.value == Node()
assert key.payload is None
def test_Node_eq():
assert Node() == Node()
assert Node('A') == Node('A', [])
def test_Node_lsfhift():
node = Node(head='A', tail=['B', ['C']])
assert (node << 1).head() == 'B'
assert (node << 2).head() == 'C'
def test_Node_is_empty():
assert Node().is_empty()
assert not Node('A').is_empty()
assert not Node('A', []).is_empty()
def test_Node_tail():
node = Node(head='A', tail=['B', ['C']])
assert node.tail() == ['B', ['C']]
def test_Node():
node = Node()
assert Node().value == (None, [])
node = Node(head='A', tail=['B', ['C']])
assert node.value == ('A', ['B', ['C']])