def test_remove_existing_provider():
um = UserManager()
um.add_provider_by_info('*****@*****.**', 'password', 'Cena', 'John',
'04253634223', 'GP')
assert (len(um.providers) == 1)
assert (um.providers[0].email == '*****@*****.**')
assert (um.get_user('*****@*****.**') is not None)
assert (um.remove_provider('*****@*****.**'))
assert (um.providers == [])
def test_remove_non_existing_provider_from_empty_list():
um = UserManager()
assert (not um.remove_provider('*****@*****.**'))
assert (um.providers == [])
def test_remove_non_existing_provider():
um = UserManager()
assert (len(um.providers) == 0)
assert (not um.remove_provider('*****@*****.**'))
assert (um.providers == [])
