psycopg2/tests/testutils.py

# testutils.py - utility module for psycopg2 testing.
#
# Copyright (C) 2010-2011 Daniele Varrazzo  <daniele.varrazzo@gmail.com>
#
# psycopg2 is free software: you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# In addition, as a special exception, the copyright holders give
# permission to link this program with the OpenSSL library (or with
# modified versions of OpenSSL that use the same license as OpenSSL),
# and distribute linked combinations including the two.
#
# You must obey the GNU Lesser General Public License in all respects for
# all of the code used other than OpenSSL.
#
# psycopg2 is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
# License for more details.


# Use unittest2 if available. Otherwise mock a skip facility with warnings.

import os
import sys

try:
    import unittest2
    unittest = unittest2
except ImportError:
    import unittest
    unittest2 = None

if hasattr(unittest, 'skipIf'):
    skip = unittest.skip
    skipIf = unittest.skipIf

else:
    import warnings

    def skipIf(cond, msg):
        def skipIf_(f):
            def skipIf__(self):
                if cond:
                    warnings.warn(msg)
                    return
                else:
                    return f(self)
            return skipIf__
        return skipIf_

    def skip(msg):
        return skipIf(True, msg)

    def skipTest(self, msg):
        warnings.warn(msg)
        return

    unittest.TestCase.skipTest = skipTest

# Silence warnings caused by the stubborness of the Python unittest maintainers
# http://bugs.python.org/issue9424
if not hasattr(unittest.TestCase, 'assert_') \
or unittest.TestCase.assert_ is not unittest.TestCase.assertTrue:
    # mavaff...
    unittest.TestCase.assert_ = unittest.TestCase.assertTrue
    unittest.TestCase.failUnless = unittest.TestCase.assertTrue
    unittest.TestCase.assertEquals = unittest.TestCase.assertEqual
    unittest.TestCase.failUnlessEqual = unittest.TestCase.assertEqual


def decorate_all_tests(cls, decorator):
    """Apply *decorator* to all the tests defined in the TestCase *cls*."""
    for n in dir(cls):
        if n.startswith('test'):
            setattr(cls, n, decorator(getattr(cls, n)))


def skip_if_no_uuid(f):
    """Decorator to skip a test if uuid is not supported by Py/PG."""
    def skip_if_no_uuid_(self):
        try:
            import uuid
        except ImportError:
            return self.skipTest("uuid not available in this Python version")

        try:
            cur = self.conn.cursor()
            cur.execute("select typname from pg_type where typname = 'uuid'")
            has = cur.fetchone()
        finally:
            self.conn.rollback()

        if has:
            return f(self)
        else:
            return self.skipTest("uuid type not available on the server")

    return skip_if_no_uuid_


def skip_if_no_pg_sleep(name):
    """Decorator to skip a test if pg_sleep is not supported by the server.

    Pass it the name of an attribute containing a connection or of a method
    returning a connection.
    """
    def skip_if_no_pg_sleep_(f):
        def skip_if_no_pg_sleep__(self):
            cnn = getattr(self, name)
            if callable(cnn):
                cnn = cnn()

            if cnn.server_version < 80200:
                return self.skipTest(
                    "server version %s doesn't support pg_sleep"
                    % cnn.server_version)

            return f(self)

        skip_if_no_pg_sleep__.__name__ = f.__name__
        return skip_if_no_pg_sleep__

    return skip_if_no_pg_sleep_


def skip_if_tpc_disabled(f):
    """Skip a test if the server has tpc support disabled."""
    def skip_if_tpc_disabled_(self):
        from psycopg2 import ProgrammingError
        cnn = self.connect()
        cur = cnn.cursor()
        try:
            cur.execute("SHOW max_prepared_transactions;")
        except ProgrammingError:
            return self.skipTest(
                "server too old: two phase transactions not supported.")
        else:
            mtp = int(cur.fetchone()[0])
        cnn.close()

        if not mtp:
            return self.skipTest(
                "server not configured for two phase transactions. "
                "set max_prepared_transactions to > 0 to run the test")
        return f(self)

    skip_if_tpc_disabled_.__name__ = f.__name__
    return skip_if_tpc_disabled_


def skip_if_no_iobase(f):
    """Skip a test if io.TextIOBase is not available."""
    def skip_if_no_iobase_(self):
        try:
            from io import TextIOBase
        except ImportError:
            return self.skipTest("io.TextIOBase not found.")
        else:
            return f(self)

    return skip_if_no_iobase_


def skip_on_python2(f):
    """Skip a test on Python 3 and following."""
    def skip_on_python2_(self):
        if sys.version_info[0] < 3:
            return self.skipTest("skipped because Python 2")
        else:
            return f(self)

    return skip_on_python2_

def skip_on_python3(f):
    """Skip a test on Python 3 and following."""
    def skip_on_python3_(self):
        if sys.version_info[0] >= 3:
            return self.skipTest("skipped because Python 3")
        else:
            return f(self)

    return skip_on_python3_

def script_to_py3(script):
    """Convert a script to Python3 syntax if required."""
    if sys.version_info[0] < 3:
        return script

    import tempfile
    f = tempfile.NamedTemporaryFile(suffix=".py")
    f.write(script.encode())
    f.flush()

    # 2to3 is way too chatty
    import logging
    logging.basicConfig(filename=os.devnull)

    from lib2to3.main import main
    if main("lib2to3.fixes", ['--no-diffs', '-w', '-n', f.name]):
        raise Exception('py3 conversion failed')

    f2 = open(f.name)
    try:
        return f2.read()
    finally:
        f2.close()