def test_bind(self):
def f(x): return toLinkedList([x, x + 1])
xs = toLinkedList([1, 2, 3])
self.assertEqual(
xs.bind(f),
toLinkedList([1, 2, 2, 3, 3, 4])
)
def test_map(self):
xs = toLinkedList([1, 2, 3])
def f(x): return x * 2
self.assertEqual(
xs.map(f),
toLinkedList([2, 4, 6])
)
def test_traverse_some(self):
xs = toLinkedList([1, 2, 3])
def add1A(x):
return some(x + 1)
self.assertEqual(Option.traverse(add1A, xs),
some(toLinkedList([2, 3, 4])))
def test_ap(self):
def f(x): return x + 1
def g(x): return x * 2
fs = toLinkedList([f, g])
xs = toLinkedList([1, 2, 3])
self.assertEqual(
fs.ap(xs),
toLinkedList([2, 3, 4, 2, 4, 6])
)
def test_functor_associativity_law(self):
xs = toLinkedList([1, 2, 3])
def f(x): return x + 1
def g(x): return x * 2
self.assertEqual(
xs.map(f).map(g),
xs.map(f |andThen| g)
)
def test_traverse_nothing(self):
xs = toLinkedList([1, 2, 3])
def oddA(x):
if x % 2 == 1:
return some(x)
else:
return nothing
self.assertEqual(Option.traverse(oddA, xs), nothing)
def test_functor_identity_law(self):
xs = toLinkedList([1, 2, 3])
self.assertEqual(
identity(xs),
xs.map(identity)
)
def test_eq_cons(self):
self.assertEqual(
cons(1, cons(2, cons(3, nil))),
toLinkedList([1, 2, 3])
)
def test_fold(self):
def add(x, y): return x + y
self.assertEqual(
toLinkedList([1, 2, 3]).fold(add, 0),
6
)
def f(x): return toLinkedList([x, x + 1]) xs = toLinkedList([1, 2, 3])
def test_sequence_nothing(self):
self.assertEqual(
Option.sequence(toLinkedList([some(1), nothing,
some(3)])), nothing)
def test_sequence_some(self):
xs = toLinkedList([some(1), some(2), some(3)])
self.assertEqual(Option.sequence(xs), some(toLinkedList([1, 2, 3])))