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Viewing changes to tests/__init__.py

  • Committer: Aaron Bentley
  • Date: 2015-01-19 15:32:33 UTC
  • mto: This revision was merged to the branch mainline in revision 804.
  • Revision ID: aaron.bentley@canonical.com-20150119153233-jjcvikwiw1dx2lak
Print error on missing environment.

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tests/__init__.py
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"""Testing helpers and base classes for better isolation."""
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from contextlib import contextmanager
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import logging
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import os
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import StringIO
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import subprocess
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import unittest
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from mock import patch
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import utility
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@contextmanager
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def stdout_guard():
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    stdout = StringIO.StringIO()
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    with patch('sys.stdout', stdout):
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        yield
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    if stdout.getvalue() != '':
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        raise AssertionError(
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            'Value written to stdout: {}'.format(stdout.getvalue()))
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def use_context(test_case, context):
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    result = context.__enter__()
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    test_case.addCleanup(context.__exit__, None, None, None)
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    return result
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class TestCase(unittest.TestCase):
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    """TestCase provides a better isolated version of unittest.TestCase."""
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    log_level = logging.INFO
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    test_environ = {}
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    def setUp(self):
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        super(TestCase, self).setUp()
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        def _must_not_Popen(*args, **kwargs):
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            """Tests may patch Popen but should never call it."""
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            self.fail("subprocess.Popen(*{!r}, **{!r}) called".format(
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                args, kwargs))
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        self.addCleanup(setattr, subprocess, "Popen", subprocess.Popen)
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        subprocess.Popen = _must_not_Popen
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        self.addCleanup(setattr, os, "environ", os.environ)
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        os.environ = dict(self.test_environ)
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        setup_test_logging(self, self.log_level)
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class FakeHomeTestCase(TestCase):
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    """FakeHomeTestCase creates an isolated home dir for Juju to use."""
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    def setUp(self):
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        super(FakeHomeTestCase, self).setUp()
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        self.home_dir = use_context(self, utility.temp_dir())
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        os.environ["HOME"] = self.home_dir
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        os.environ["PATH"] = os.path.join(self.home_dir, ".local", "bin")
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        os.mkdir(os.path.join(self.home_dir, ".juju"))
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def setup_test_logging(testcase, level=None):
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    log = logging.getLogger()
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    testcase.addCleanup(setattr, log, 'handlers', log.handlers)
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    log.handlers = []
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    testcase.log_stream = StringIO.StringIO()
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    handler = logging.StreamHandler(testcase.log_stream)
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    handler.setFormatter(logging.Formatter("%(levelname)s %(message)s"))
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    log.addHandler(handler)
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    if level is not None:
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        testcase.addCleanup(log.setLevel, log.level)
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        log.setLevel(level)
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# suppress nosetests
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setup_test_logging.__test__ = False
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@contextmanager
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def parse_error(test_case):
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    stderr = StringIO.StringIO()
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    with test_case.assertRaises(SystemExit):
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        with patch('sys.stderr', stderr):
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            yield stderr
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@contextmanager
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def temp_os_env(key, value):
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    org_value = os.environ.get(key, '')
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    os.environ[key] = value
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    try:
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        yield
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    finally:
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        os.environ[key] = org_value