internal/lib/utils_test.py

#!/usr/bin/env python
#
# Copyright 2016 - The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Tests for acloud.internal.lib.utils."""

import errno
import getpass
import os
import shutil
import subprocess
import tempfile
import time

import unittest
import mock

from acloud.internal.lib import driver_test_lib
from acloud.internal.lib import utils


class UtilsTest(driver_test_lib.BaseDriverTest):
    """Test Utils."""

    def TestTempDirSuccess(self):
        """Test create a temp dir."""
        self.Patch(os, "chmod")
        self.Patch(tempfile, "mkdtemp", return_value="/tmp/tempdir")
        self.Patch(shutil, "rmtree")
        with utils.TempDir():
            pass
        # Verify.
        tempfile.mkdtemp.assert_called_once()  # pylint: disable=no-member
        shutil.rmtree.assert_called_with("/tmp/tempdir")  # pylint: disable=no-member

    def TestTempDirExceptionRaised(self):
        """Test create a temp dir and exception is raised within with-clause."""
        self.Patch(os, "chmod")
        self.Patch(tempfile, "mkdtemp", return_value="/tmp/tempdir")
        self.Patch(shutil, "rmtree")

        class ExpectedException(Exception):
            """Expected exception."""
            pass

        def _Call():
            with utils.TempDir():
                raise ExpectedException("Expected exception.")

        # Verify. ExpectedException should be raised.
        self.assertRaises(ExpectedException, _Call)
        tempfile.mkdtemp.assert_called_once()  # pylint: disable=no-member
        shutil.rmtree.assert_called_with("/tmp/tempdir")  #pylint: disable=no-member

    def testTempDirWhenDeleteTempDirNoLongerExist(self):  # pylint: disable=invalid-name
        """Test create a temp dir and dir no longer exists during deletion."""
        self.Patch(os, "chmod")
        self.Patch(tempfile, "mkdtemp", return_value="/tmp/tempdir")
        expected_error = EnvironmentError()
        expected_error.errno = errno.ENOENT
        self.Patch(shutil, "rmtree", side_effect=expected_error)

        def _Call():
            with utils.TempDir():
                pass

        # Verify no exception should be raised when rmtree raises
        # EnvironmentError with errno.ENOENT, i.e.
        # directory no longer exists.
        _Call()
        tempfile.mkdtemp.assert_called_once()  #pylint: disable=no-member
        shutil.rmtree.assert_called_with("/tmp/tempdir")  #pylint: disable=no-member

    def testTempDirWhenDeleteEncounterError(self):
        """Test create a temp dir and encoutered error during deletion."""
        self.Patch(os, "chmod")
        self.Patch(tempfile, "mkdtemp", return_value="/tmp/tempdir")
        expected_error = OSError("Expected OS Error")
        self.Patch(shutil, "rmtree", side_effect=expected_error)

        def _Call():
            with utils.TempDir():
                pass

        # Verify OSError should be raised.
        self.assertRaises(OSError, _Call)
        tempfile.mkdtemp.assert_called_once()  #pylint: disable=no-member
        shutil.rmtree.assert_called_with("/tmp/tempdir")  #pylint: disable=no-member

    def testTempDirOrininalErrorRaised(self):
        """Test original error is raised even if tmp dir deletion failed."""
        self.Patch(os, "chmod")
        self.Patch(tempfile, "mkdtemp", return_value="/tmp/tempdir")
        expected_error = OSError("Expected OS Error")
        self.Patch(shutil, "rmtree", side_effect=expected_error)

        class ExpectedException(Exception):
            """Expected exception."""
            pass

        def _Call():
            with utils.TempDir():
                raise ExpectedException("Expected Exception")

        # Verify.
        # ExpectedException should be raised, and OSError
        # should not be raised.
        self.assertRaises(ExpectedException, _Call)
        tempfile.mkdtemp.assert_called_once()  #pylint: disable=no-member
        shutil.rmtree.assert_called_with("/tmp/tempdir")  #pylint: disable=no-member

    def testCreateSshKeyPairKeyAlreadyExists(self):  #pylint: disable=invalid-name
        """Test when the key pair already exists."""
        public_key = "/fake/public_key"
        private_key = "/fake/private_key"
        self.Patch(
            os.path, "exists", side_effect=lambda path: path == public_key)
        self.Patch(subprocess, "check_call")
        utils.CreateSshKeyPairIfNotExist(private_key, public_key)
        self.assertEqual(subprocess.check_call.call_count, 0)  #pylint: disable=no-member

    def testCreateSshKeyPairKeyAreCreated(self):
        """Test when the key pair created."""
        public_key = "/fake/public_key"
        private_key = "/fake/private_key"
        self.Patch(os.path, "exists", return_value=False)
        self.Patch(subprocess, "check_call")
        self.Patch(os, "rename")
        utils.CreateSshKeyPairIfNotExist(private_key, public_key)
        self.assertEqual(subprocess.check_call.call_count, 1)  #pylint: disable=no-member
        subprocess.check_call.assert_called_with(  #pylint: disable=no-member
            utils.SSH_KEYGEN_CMD +
            ["-C", getpass.getuser(), "-f", private_key],
            stdout=mock.ANY,
            stderr=mock.ANY)

    def TestRetryOnException(self):
        """Test Retry."""

        def _IsValueError(exc):
            return isinstance(exc, ValueError)

        num_retry = 5

        @utils.RetryOnException(_IsValueError, num_retry)
        def _RaiseAndRetry(sentinel):
            sentinel.alert()
            raise ValueError("Fake error.")

        sentinel = mock.MagicMock()
        self.assertRaises(ValueError, _RaiseAndRetry, sentinel)
        self.assertEqual(1 + num_retry, sentinel.alert.call_count)

    def testRetryExceptionType(self):
        """Test RetryExceptionType function."""

        def _RaiseAndRetry(sentinel):
            sentinel.alert()
            raise ValueError("Fake error.")

        num_retry = 5
        sentinel = mock.MagicMock()
        self.assertRaises(
            ValueError,
            utils.RetryExceptionType, (KeyError, ValueError),
            num_retry,
            _RaiseAndRetry,
            0, # sleep_multiplier
            1, # retry_backoff_factor
            sentinel=sentinel)
        self.assertEqual(1 + num_retry, sentinel.alert.call_count)

    def testRetry(self):
        """Test Retry."""
        mock_sleep = self.Patch(time, "sleep")

        def _RaiseAndRetry(sentinel):
            sentinel.alert()
            raise ValueError("Fake error.")

        num_retry = 5
        sentinel = mock.MagicMock()
        self.assertRaises(
            ValueError,
            utils.RetryExceptionType, (ValueError, KeyError),
            num_retry,
            _RaiseAndRetry,
            1, # sleep_multiplier
            2, # retry_backoff_factor
            sentinel=sentinel)

        self.assertEqual(1 + num_retry, sentinel.alert.call_count)
        mock_sleep.assert_has_calls(
            [
                mock.call(1),
                mock.call(2),
                mock.call(4),
                mock.call(8),
                mock.call(16)
            ])


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