import itertools

from dogpile.cache.api import NO_VALUE
from dogpile.testing import eq_
from dogpile.testing.fixtures import _GenericBackendFixture


class NullBackendTest(_GenericBackendFixture):
    backend = "dogpile.cache.null"

    def test_get(self):
        reg = self._region()

        eq_(reg.get("some key"), NO_VALUE)

    def test_set(self):
        reg = self._region()
        reg.set("some key", "some value")
        eq_(reg.get("some key"), NO_VALUE)

    def test_delete(self):
        reg = self._region()
        reg.delete("some key")
        eq_(reg.get("some key"), NO_VALUE)

    def test_get_multi(self):
        reg = self._region()

        eq_(reg.get_multi(["a", "b", "c"]), [NO_VALUE, NO_VALUE, NO_VALUE])

    def test_set_multi(self):
        reg = self._region()
        reg.set_multi({"a": 1, "b": 2, "c": 3})
        eq_(reg.get_multi(["a", "b", "c"]), [NO_VALUE, NO_VALUE, NO_VALUE])

    def test_delete_multi(self):
        reg = self._region()
        reg.delete_multi(["a", "b", "c"])
        eq_(reg.get_multi(["a", "b", "c"]), [NO_VALUE, NO_VALUE, NO_VALUE])

    def test_decorator(self):
        reg = self._region()

        counter = itertools.count(1)

        @reg.cache_on_arguments()
        def go(a, b):
            val = next(counter)
            return val, a, b

        eq_(go(1, 2), (1, 1, 2))
        eq_(go(1, 2), (2, 1, 2))
        eq_(go(1, 3), (3, 1, 3))

    def test_mutex(self):
        backend = self._backend()
        mutex = backend.get_mutex("foo")

        ac = mutex.acquire()
        assert ac
        mutex.release()

        ac2 = mutex.acquire(False)
        assert ac2
        mutex.release()

    def test_mutex_doesnt_actually_lock(self):
        backend = self._backend()
        mutex = backend.get_mutex("foo")

        ac = mutex.acquire()
        assert ac

        ac2 = mutex.acquire(False)
        assert ac2
        mutex.release()