def test_next():
l = Slist()
l.prepend("Bob")
l.prepend("Amy")
l.prepend("Carol")
assert l.head.key == "Carol"
head_next = l.head.next
assert head_next.key == "Amy"
last = head_next.next
assert last.key == "Bob"
def test_delete_next_reassignment():
l = Slist()
l.prepend("Bob")
l.prepend("Dave")
l.prepend("Amy")
l.prepend("Carol")
l.delete("Amy")
l.delete("Dave")
assert l.head.next.key == "Bob"
def test_delete():
l = Slist()
l.prepend("Bob")
l.prepend("Amy")
l.prepend("Carol")
l.delete("Carol")
assert l.head.key == "Amy"
l.delete("Bob")
assert l.head.next is None
l = Slist()
l.prepend("Bob")
l.prepend("Amy")
l.prepend("Carol")
with pytest.raises(ValueError):
l.delete("Edgar")
l = Slist()
with pytest.raises(ValueError):
l.delete("Edgar")
def test_search():
l = Slist()
l.prepend("Bob")
l.prepend("Amy")
l.prepend("Carol")
found = l.contains("Bob")
assert found is True
found = l.contains("Amy")
assert found is True
found = l.contains("Bob")
assert found is True
l = Slist()
l.prepend("Bob")
l.prepend("Amy")
found = l.contains("Bob")
assert found is True
found = l.contains("Dave")
assert found is False
def test_prepend():
l = Slist()
l.prepend("Bob")
assert l.head.key == "Bob"
assert l.head.next is None
