import unittest
import sys
from unittest import TestCase

try:
    # Python 3.x
    from unittest.mock import patch, mock_open
    open_name = 'builtins.open'
except ImportError:
    # Python 2.7
    from mock import patch, mock_open
    open_name = '__builtin__.open'

import pidfile
import os
import psutil

builtins_open = open


def open_patcher(data):
    def patched_open(*args, **kwargs):
        if args[0] == 'pidfile':
            return mock_open(read_data=data)(*args, **kwargs)
        else:
            return builtins_open(*args, **kwargs)
    return patched_open


def open_patcher_exception():
    def patched_open(*args, **kwargs):
        if args[0] == 'pidfile':
            mo = mock_open()
            mo.return_value.read.side_effect = OSError
            return mo(*args, **kwargs)
        else:
            return builtins_open(*args, **kwargs)
    return patched_open


class PIDFileTestCase(TestCase):
    @patch(open_name, new=open_patcher('1'))
    @patch('os.path.exists')
    def test_pidfile_not_exists(self, exists_mock):
        exists_mock.return_value = False
        with pidfile.PIDFile():
            assert True

    @patch(open_name, new=open_patcher('1'))
    @patch('psutil.pid_exists')
    @patch('psutil.Process')
    @patch('os.path.exists')
    def test_pidfile_exists_process_running(self, exists_mock, Process_mock,
                                            pid_exists_mock):
        exists_mock.return_value = True
        pid_exists_mock.return_value = True
        Process_mock.return_value = psutil.Process(os.getpid())
        with self.assertRaises(pidfile.AlreadyRunningError):
            with pidfile.PIDFile():
                assert True

    @patch(open_name, new=open_patcher('1'))
    @patch('psutil.pid_exists')
    @patch('os.path.exists')
    def test_pidfile_exists_process_not_running(self, exists_mock,
                                                pid_exists_mock):
        exists_mock.return_value = True
        pid_exists_mock.return_value = False
        with pidfile.PIDFile():
            assert True

    @patch(open_name, new=open_patcher(''))
    @patch('psutil.pid_exists')
    @patch('os.path.exists')
    def test_pidfile_exists_empty(self, exists_mock, pid_exists_mock):
        exists_mock.return_value = True
        pid_exists_mock.return_value = True
        with pidfile.PIDFile():
            assert True

    @patch(open_name, new=open_patcher_exception())
    @patch('psutil.pid_exists')
    @patch('os.path.exists')
    def test_pidfile_exists_read_fail(self, exists_mock, pid_exists_mock):
        exists_mock.return_value = True
        pid_exists_mock.return_value = True
        with pidfile.PIDFile():
            assert True

def main(out = sys.stderr, verbosity = 2):
    loader = unittest.TestLoader()
  
    suite = loader.loadTestsFromModule(sys.modules[__name__])
    unittest.TextTestRunner(out, verbosity = verbosity).run(suite)
      
if __name__ == '__main__':
    with open(sys.argv[1], 'w') as f:
        main(f)