from __future__ import with_statement
import unittest
import weakref
import time
from eventlet.api import sleep, timeout, TimeoutError, _SilentException
DELAY = 0.01

class Error(Exception):
    pass
 
class Test(unittest.TestCase):

    def test_api(self):
        # Nothing happens if with-block finishes before the timeout expires 
        with timeout(DELAY*2):
            sleep(DELAY)
        sleep(DELAY*2) # check if timer was actually cancelled

        # An exception will be raised if it's not
        try:
            with timeout(DELAY):
                sleep(DELAY*2)
        except TimeoutError:
            pass
        else:
            assert False, 'must raise TimeoutError'

        # You can customize the exception raised:
        try:
            with timeout(DELAY, IOError("Operation takes way too long")):
                sleep(DELAY*2)
        except IOError, ex:
            assert str(ex)=="Operation takes way too long", repr(ex)

        # Providing classes instead of values should be possible too:
        try:
            with timeout(DELAY, ValueError):
                sleep(DELAY*2)
        except ValueError:
            pass

        # basically, anything that greenlet.throw accepts work:
        try:
            1/0
        except:
            try:
                with timeout(DELAY, *sys.exc_info()):
                    sleep(DELAY*2)
                    assert 'should not get there'
                assert 'should not get there'
            except ZeroDivisionError:
                pass
        else:
            assert 'should not get there'

        # It's possible to cancel the timer inside the block:
        with timeout(DELAY) as timer:
            timer.cancel()
            sleep(DELAY*2)
         
        # To silent the exception, pass None as second parameter. The with-block
        # will be interrupted with _SilentException, but it won't be propogated
        # outside.
        XDELAY=0.1
        start = time.time()
        with timeout(XDELAY, None):
            sleep(XDELAY*2)
        delta = (time.time()-start)
        assert delta<XDELAY*2, delta

    def test_ref(self):
        err = Error()
        err_ref = weakref.ref(err)
        with timeout(DELAY*2, err):
            sleep(DELAY)
        del err
        assert not err_ref(), repr(err_ref())

    def test_nested_timeout(self):
        with timeout(DELAY, None):
            with timeout(DELAY*2, None):
                sleep(DELAY*3)
            assert False, 'should not get there'

        with timeout(DELAY, _SilentException()):
            with timeout(DELAY*2, _SilentException()):
                sleep(DELAY*3)
            assert False, 'should not get there'

        # this case fails and there's no intent to fix it.
        # just don't do it like that
        #with timeout(DELAY, _SilentException):
        #    with timeout(DELAY*2, _SilentException):
        #        sleep(DELAY*3)
        #    assert False, 'should not get there'


if __name__=='__main__':
    unittest.main()