# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
Tests for L{twisted.internet.default}.
"""

from __future__ import division, absolute_import

import select, sys
from twisted.trial.unittest import SynchronousTestCase
from twisted.python.runtime import Platform
from twisted.internet import default
from twisted.internet.default import _getInstallFunction, install
from twisted.internet.test.test_main import NoReactor
from twisted.internet.interfaces import IReactorCore

unix = Platform('posix', 'other')
linux = Platform('posix', 'linux2')
windows = Platform('nt', 'win32')
osx = Platform('posix', 'darwin')


class PollReactorTests(SynchronousTestCase):
"""
Tests for the cases of L{twisted.internet.default._getInstallFunction}
in which it picks the poll(2) or epoll(7)-based reactors.
"""

def assertIsPoll(self, install):
"""
Assert the given function will install the poll() reactor, or select()
if poll() is unavailable.
"""
if hasattr(select, "poll"):
self.assertEqual(
install.__module__, 'twisted.internet.pollreactor')
else:
self.assertEqual(
install.__module__, 'twisted.internet.selectreactor')


def test_unix(self):
"""
L{_getInstallFunction} chooses the poll reactor on arbitrary Unix
platforms, falling back to select(2) if it is unavailable.
"""
install = _getInstallFunction(unix)
self.assertIsPoll(install)


def test_linux(self):
"""
L{_getInstallFunction} chooses the epoll reactor on Linux, or poll if
epoll is unavailable.
"""
install = _getInstallFunction(linux)
try:
from twisted.internet import epollreactor
except ImportError:
self.assertIsPoll(install)
else:
self.assertEqual(
install.__module__, 'twisted.internet.epollreactor')



class SelectReactorTests(SynchronousTestCase):
"""
Tests for the cases of L{twisted.internet.default._getInstallFunction}
in which it picks the select(2)-based reactor.
"""
def test_osx(self):
"""
L{_getInstallFunction} chooses the select reactor on OS X.
"""
install = _getInstallFunction(osx)
self.assertEqual(
install.__module__, 'twisted.internet.selectreactor')


def test_windows(self):
"""
L{_getInstallFunction} chooses the select reactor on Windows.
"""
install = _getInstallFunction(windows)
self.assertEqual(
install.__module__, 'twisted.internet.selectreactor')



class InstallationTests(SynchronousTestCase):
"""
Tests for actual installation of the reactor.
"""

def test_install(self):
"""
L{install} installs a reactor.
"""
with NoReactor():
install()
self.assertIn("twisted.internet.reactor", sys.modules)


def test_reactor(self):
"""
Importing L{twisted.internet.reactor} installs the default reactor if
none is installed.
"""
installed = []
def installer():
installed.append(True)
return install()
self.patch(default, "install", installer)

with NoReactor():
from twisted.internet import reactor
self.assertTrue(IReactorCore.providedBy(reactor))
self.assertEqual(installed, [True])