def test_mplus_with_nothing_and_just(self):
self.givenMonoids(Nothing, First(Just(1)))
self.ensure_mconcat_equals(First(Just(1)))
def test_mplus_with_two_just_values(self):
self.givenMonoids(First(Just(1)), First(Just(2)))
self.ensure_mconcat_equals(First(Just(1)))
def test_left_identity(self):
self.givenMonoid(First(Just(9)))
self.ensure_zero_plus_monoid_equals(First(Just(9)))
def test_associativity(self):
self.givenMonoids(First(Just(1)), First(Just(2)), First(Just(3)))
self.ensure_associativity()
def test_mzero(self):
self.givenMonoid(First)
self.get_mzero()
self.ensure_mzero_is(First(Nothing))