def test_noIntersection_returnsNone():
a = Node(3)
a.next = Node(4)
a.next.next = Node(10)
b = Node(1)
b.next = Node(2)
assert intersection(a, b) == None
def test_firstIntersectsSecond_returnsIntersection():
b = Node(1)
b.next = Node(2)
b.next.next = Node(3)
b.next.next.next = Node(4)
a = Node(6)
a.next = b.next.next
c = intersection(a, b)
assert c is not None
assert c.val == 3
assert c.next.val == 4
def test_secondIntersectsFirst_returnsIntersection():
a = Node(1)
a.next = Node(2)
a.next.next = Node(3)
a.next.next.next = Node(4)
b = Node(6)
b.next = a.next.next
c = intersection(a, b)
assert c is not None
assert c.val == 3
assert c.next.val == 4
def test_emptyFirstParam_returnsNone():
a = Node(3)
assert intersection(None, a) == None
def test_emptySecondParam_returnsNone():
a = Node(3)
assert intersection(a, None) == None