def test_associativity_law(self):
a = ExactlyOne(1)
def f(x):
return x + 1
def g(x):
return x * 2
self.assertEqual(a.map(f).map(g), a.map(f | andThen | g))
def test_replaceWithA(self):
self.assertEqual(
ExactlyOne(1).replaceWithA(ExactlyOne(2)).value,
ExactlyOne(2).value)
def test_fold(self):
def add(x, y):
return x + y
self.assertEqual(ExactlyOne(2).fold(add, 1), 3)
def test_contains(self):
self.assertEqual(ExactlyOne(0).contains(1), False)
self.assertEqual(ExactlyOne(1).contains(1), True)
def test_isEmpty(self):
self.assertFalse(ExactlyOne(0).isEmpty())
def test_length(self):
self.assertEqual(ExactlyOne(0).length(), 1)
def test_identity_law(self):
a = ExactlyOne(1)
self.assertEqual(identity(a), a.map(identity))
def test_void(self):
assert ExactlyOne(1).void() == ExactlyOne(())
def test_replaceWith(self):
assert ExactlyOne(1).replaceWith(2) == ExactlyOne(2)