patroni/tests/test_postgresql.py

import mock  # for the mock.call method, importing it without a namespace breaks python3
import os
import psycopg2
import shutil
import subprocess
import unittest

from mock import Mock, MagicMock, PropertyMock, patch, mock_open
from patroni.dcs import Cluster, Leader, Member
from patroni.exceptions import PostgresException, PostgresConnectionException
from patroni.postgresql import Postgresql
from patroni.utils import RetryFailedError
from six.moves import builtins


class MockCursor(object):

    def __init__(self, connection):
        self.connection = connection
        self.closed = False
        self.results = []

    def execute(self, sql, *params):
        if sql.startswith('blabla') or sql == 'CHECKPOINT':
            raise psycopg2.OperationalError()
        elif sql.startswith('RetryFailedError'):
            raise RetryFailedError('retry')
        elif sql.startswith('SELECT slot_name'):
            self.results = [('blabla',), ('foobar',)]
        elif sql.startswith('SELECT pg_xlog_location_diff'):
            self.results = [(0,)]
        elif sql == 'SELECT pg_is_in_recovery()':
            self.results = [(False, )]
        elif sql.startswith('WITH replication_info AS ('):
            replication_info = '[{"application_name":"walreceiver","client_addr":"1.2.3.4",' +\
                               '"state":"streaming","sync_state":"async","sync_priority":0}]'
            self.results = [('', True, '', '', '', '', False, replication_info)]
        elif sql.startswith('SELECT name, setting'):
            self.results = [('wal_segment_size', '2048', '8kB', 'integer', 'internal'),
                            ('search_path', 'public', None, 'string', 'user'),
                            ('port', '5433', None, 'integer', 'postmaster'),
                            ('listen_addresses', '*', None, 'string', 'postmaster'),
                            ('autovacuum', 'on', None, 'bool', 'sighup')]
        else:
            self.results = [(None, None, None, None, None, None, None, None, None, None)]

    def fetchone(self):
        return self.results[0]

    def fetchall(self):
        return self.results

    def __iter__(self):
        for i in self.results:
            yield i

    def __enter__(self):
        return self

    def __exit__(self, *args):
        pass


class MockConnect(object):

    server_version = '99999'
    autocommit = False
    closed = 0

    def cursor(self):
        return MockCursor(self)

    def __enter__(self):
        return self

    def __exit__(self, *args):
        pass

    @staticmethod
    def close():
        pass


def pg_controldata_string(*args, **kwargs):
    return b"""
pg_control version number:            942
Catalog version number:               201509161
Database system identifier:           6200971513092291716
Database cluster state:               shut down in recovery
pg_control last modified:             Fri Oct  2 10:57:06 2015
Latest checkpoint location:           0/30000C8
Prior checkpoint location:            0/2000060
Latest checkpoint's REDO location:    0/3000090
Latest checkpoint's REDO WAL file:    000000020000000000000003
Latest checkpoint's TimeLineID:       2
Latest checkpoint's PrevTimeLineID:   2
Latest checkpoint's full_page_writes: on
Latest checkpoint's NextXID:          0/943
Latest checkpoint's NextOID:          24576
Latest checkpoint's NextMultiXactId:  1
Latest checkpoint's NextMultiOffset:  0
Latest checkpoint's oldestXID:        931
Latest checkpoint's oldestXID's DB:   1
Latest checkpoint's oldestActiveXID:  943
Latest checkpoint's oldestMultiXid:   1
Latest checkpoint's oldestMulti's DB: 1
Latest checkpoint's oldestCommitTs:   0
Latest checkpoint's newestCommitTs:   0
Time of latest checkpoint:            Fri Oct  2 10:56:54 2015
Fake LSN counter for unlogged rels:   0/1
Minimum recovery ending location:     0/30241F8
Min recovery ending loc's timeline:   2
Backup start location:                0/0
Backup end location:                  0/0
End-of-backup record required:        no
wal_level setting:                    hot_standby
Current wal_log_hints setting:                on
Current max_connections setting:              100
Current max_worker_processes setting:         8
Current max_prepared_xacts setting:           0
Current max_locks_per_xact setting:           64
Current track_commit_timestamp setting:       off
Maximum data alignment:               8
Database block size:                  8192
Blocks per segment of large relation: 131072
WAL block size:                       8192
Bytes per WAL segment:                16777216
Maximum length of identifiers:        64
Maximum columns in an index:          32
Maximum size of a TOAST chunk:        1996
Size of a large-object chunk:         2048
Date/time type storage:               64-bit integers
Float4 argument passing:              by value
Float8 argument passing:              by value
Data page checksum version:           0
"""


def postmaster_opts_string(*args, **kwargs):
    return '/usr/local/pgsql/bin/postgres "-D" "data/postgresql0" "--listen_addresses=127.0.0.1" \
"--port=5432" "--hot_standby=on" "--wal_keep_segments=8" "--wal_level=hot_standby" \
"--archive_command=mkdir -p ../wal_archive && cp %p ../wal_archive/%f" "--wal_log_hints=on" \
"--max_wal_senders=5" "--archive_timeout=1800s" "--archive_mode=on" "--max_replication_slots=5"\n'


def psycopg2_connect(*args, **kwargs):
    return MockConnect()


def fake_listdir(path):
    return ["a", "b", "c"] if path.endswith('pg_xlog/archive_status') else []


@patch('subprocess.call', Mock(return_value=0))
@patch('psycopg2.connect', psycopg2_connect)
class TestPostgresql(unittest.TestCase):
    _PARAMETERS = {'wal_level': 'hot_standby', 'max_replication_slots': 5, 'f.oo': 'bar',
                   'search_path': 'public', 'hot_standby': 'on', 'max_wal_senders': 5,
                   'wal_keep_segments': 8, 'wal_log_hints': 'on', 'max_locks_per_transaction': 64,
                   'max_worker_processes': 8, 'max_connections': 100, 'max_prepared_transactions': 0}

    @patch('subprocess.call', Mock(return_value=0))
    @patch('psycopg2.connect', psycopg2_connect)
    @patch('os.rename', Mock())
    @patch.object(Postgresql, 'get_major_version', Mock(return_value=9.4))
    @patch.object(Postgresql, 'is_running', Mock(return_value=True))
    def setUp(self):
        self.data_dir = 'data/test0'
        if not os.path.exists(self.data_dir):
            os.makedirs(self.data_dir)
        self.p = Postgresql({'name': 'test0', 'scope': 'batman', 'data_dir': self.data_dir, 'retry_timeout': 10,
                             'listen': '127.0.0.1, *:5432', 'connect_address': '127.0.0.2:5432',
                             'authentication': {'superuser': {'username': 'test', 'password': 'test'},
                                                'replication': {'username': 'replicator', 'password': 'rep-pass'}},
                             'remove_data_directory_on_rewind_failure': True,
                             'use_pg_rewind': True, 'pg_ctl_timeout': 'bla',
                             'parameters': self._PARAMETERS,
                             'recovery_conf': {'foo': 'bar'},
                             'callbacks': {'on_start': 'true', 'on_stop': 'true',
                                           'on_restart': 'true', 'on_role_change': 'true',
                                           'on_reload': 'true'
                                           },
                             'restore': 'true'})
        self.leadermem = Member(0, 'leader', 28, {'conn_url': 'postgres://replicator:[email protected]:5435/postgres'})
        self.leader = Leader(-1, 28, self.leadermem)
        self.other = Member(0, 'test-1', 28, {'conn_url': 'postgres://replicator:[email protected]:5433/postgres',
                            'tags': {'replicatefrom': 'leader'}})
        self.me = Member(0, 'test0', 28, {'conn_url': 'postgres://replicator:[email protected]:5434/postgres'})

    def tearDown(self):
        shutil.rmtree('data')

    def test_get_initdb_options(self):
        self.assertEquals(self.p.get_initdb_options([{'encoding': 'UTF8'}, 'data-checksums']),
                          ['--encoding=UTF8', '--data-checksums'])
        self.assertRaises(Exception, self.p.get_initdb_options, [{'pgdata': 'bar'}])
        self.assertRaises(Exception, self.p.get_initdb_options, [{'foo': 'bar', 1: 2}])
        self.assertRaises(Exception, self.p.get_initdb_options, [1])

    @patch('os.path.exists', Mock(return_value=True))
    @patch('os.unlink', Mock())
    def test_delete_trigger_file(self):
        self.p.delete_trigger_file()

    @patch.object(Postgresql, 'is_running')
    def test_start(self, mock_is_running):
        mock_is_running.return_value = True
        self.assertTrue(self.p.start())
        mock_is_running.return_value = False
        open(os.path.join(self.data_dir, 'postmaster.pid'), 'w').close()
        pg_conf = os.path.join(self.data_dir, 'postgresql.conf')
        open(pg_conf, 'w').close()
        self.assertTrue(self.p.start())
        with open(pg_conf) as f:
            lines = f.readlines()
            self.assertTrue("f.oo = 'bar'\n" in lines)

    @patch.object(Postgresql, 'is_running')
    def test_stop(self, mock_is_running):
        mock_is_running.return_value = True
        self.assertTrue(self.p.stop())
        with patch('subprocess.call', Mock(return_value=1)):
            mock_is_running.return_value = False
            self.assertTrue(self.p.stop())

    def test_restart(self):
        self.p.start = Mock(return_value=False)
        self.assertFalse(self.p.restart())
        self.assertEquals(self.p.state, 'restart failed (restarting)')

    @patch.object(builtins, 'open', MagicMock())
    def test_write_pgpass(self):
        self.p.write_pgpass({'host': 'localhost', 'port': '5432', 'user': 'foo', 'password': 'bar'})

    def test_checkpoint(self):
        with patch.object(MockCursor, 'fetchone', Mock(return_value=(True, ))):
            self.assertEquals(self.p.checkpoint({'user': 'postgres'}), 'is_in_recovery=true')
        with patch.object(MockCursor, 'execute', Mock(return_value=None)):
            self.assertIsNone(self.p.checkpoint())
        self.assertEquals(self.p.checkpoint(), 'not accessible or not healty')

    @patch('subprocess.call', side_effect=OSError)
    @patch('patroni.postgresql.Postgresql.write_pgpass', MagicMock(return_value=dict()))
    def test_pg_rewind(self, mock_call):
        r = {'user': '', 'host': '', 'port': '', 'database': '', 'password': ''}
        self.assertTrue(self.p.rewind(r))
        subprocess.call = mock_call
        self.assertFalse(self.p.rewind(r))

    @patch('os.unlink', Mock(return_value=True))
    @patch('subprocess.check_output', Mock(return_value=0, side_effect=pg_controldata_string))
    @patch.object(Postgresql, 'remove_data_directory', Mock(return_value=True))
    @patch.object(Postgresql, 'single_user_mode', Mock(return_value=1))
    @patch.object(Postgresql, 'write_pgpass', Mock(return_value={}))
    @patch.object(Postgresql, 'is_running', Mock(return_value=True))
    @patch.object(Postgresql, 'can_rewind', PropertyMock(return_value=True))
    @patch.object(Postgresql, 'rewind', return_value=False)
    def test_follow(self, mock_pg_rewind):
        with patch.object(Postgresql, 'check_recovery_conf', Mock(return_value=True)):
            self.assertTrue(self.p.follow(None, None))  # nothing to do, recovery.conf has good primary_conninfo

        self.p.follow(self.me, self.me)  # follow is called when the node is holding leader lock

        with patch.object(Postgresql, 'restart', Mock(return_value=False)):
            self.p.set_role('replica')
            self.p.follow(None, None)  # restart without rewind

        with patch.object(Postgresql, 'stop', Mock(return_value=False)):
            self.p.follow(self.leader, self.leader, need_rewind=True)  # failed to stop postgres

        self.p.follow(self.leader, self.leader)  # "leader" is not accessible or is_in_recovery

        with patch.object(Postgresql, 'checkpoint', Mock(return_value=None)):
            self.p.follow(self.leader, self.leader)
            mock_pg_rewind.return_value = True
            self.p.follow(self.leader, self.leader, need_rewind=True)

        self.p.follow(None, None)  # check_recovery_conf...

    @patch('subprocess.check_output', Mock(return_value=0, side_effect=pg_controldata_string))
    def test_can_rewind(self):
        with patch('subprocess.call', MagicMock(return_value=1)):
            self.assertFalse(self.p.can_rewind)
        with patch('subprocess.call', side_effect=OSError):
            self.assertFalse(self.p.can_rewind)
        with patch.object(Postgresql, 'controldata', Mock(return_value={'wal_log_hints setting': 'on'})):
            self.assertTrue(self.p.can_rewind)
        self.p.config['use_pg_rewind'] = False
        self.assertFalse(self.p.can_rewind)

    @patch('time.sleep', Mock())
    @patch.object(Postgresql, 'remove_data_directory', Mock(return_value=True))
    def test_create_replica(self):
        self.p.delete_trigger_file = Mock(side_effect=OSError)
        with patch('subprocess.call', Mock(side_effect=[1, 0])):
            self.assertEquals(self.p.create_replica(self.leader), 0)
        with patch('subprocess.call', Mock(side_effect=[Exception(), 0])):
            self.assertEquals(self.p.create_replica(self.leader), 0)

        self.p.config['create_replica_method'] = ['wale', 'basebackup']
        self.p.config['wale'] = {'command': 'foo'}
        with patch('subprocess.call', Mock(return_value=0)):
            self.assertEquals(self.p.create_replica(self.leader), 0)
            del self.p.config['wale']
            self.assertEquals(self.p.create_replica(self.leader), 0)

        with patch('subprocess.call', Mock(side_effect=Exception("foo"))):
            self.assertEquals(self.p.create_replica(self.leader), 1)

        with patch('subprocess.call', Mock(return_value=1)):
            self.assertEquals(self.p.create_replica(self.leader), 1)

    @patch.object(Postgresql, 'is_running', Mock(return_value=True))
    def test_sync_replication_slots(self):
        self.p.start()
        cluster = Cluster(True, None, self.leader, 0, [self.me, self.other, self.leadermem], None)
        with mock.patch('patroni.postgresql.Postgresql._query', Mock(side_effect=psycopg2.OperationalError)):
            self.p.sync_replication_slots(cluster)
        self.p.sync_replication_slots(cluster)
        with mock.patch('patroni.postgresql.Postgresql.role', new_callable=PropertyMock(return_value='replica')):
            self.p.sync_replication_slots(cluster)
        with mock.patch('patroni.postgresql.logger.error', new_callable=Mock()) as errorlog_mock:
            self.p.query = Mock()
            alias1 = Member(0, 'test-3', 28, {'conn_url': 'postgres://replicator:[email protected]:5436/postgres'})
            alias2 = Member(0, 'test.3', 28, {'conn_url': 'postgres://replicator:[email protected]:5436/postgres'})
            cluster.members.extend([alias1, alias2])
            self.p.sync_replication_slots(cluster)
            errorlog_mock.assert_called_once()
            assert "test-3" in errorlog_mock.call_args[0][1]
            assert "test.3" in errorlog_mock.call_args[0][1]

    @patch.object(MockConnect, 'closed', 2)
    def test__query(self):
        self.assertRaises(PostgresConnectionException, self.p._query, 'blabla')
        self.p._state = 'restarting'
        self.assertRaises(RetryFailedError, self.p._query, 'blabla')

    def test_query(self):
        self.p.query('select 1')
        self.assertRaises(PostgresConnectionException, self.p.query, 'RetryFailedError')
        self.assertRaises(psycopg2.OperationalError, self.p.query, 'blabla')

    def test_is_leader(self):
        self.assertTrue(self.p.is_leader())

    def test_reload(self):
        self.assertTrue(self.p.reload())

    @patch.object(Postgresql, 'is_running')
    def test_is_healthy(self, mock_is_running):
        mock_is_running.return_value = True
        self.assertTrue(self.p.is_healthy())
        mock_is_running.return_value = False
        self.assertFalse(self.p.is_healthy())

    def test_promote(self):
        self.p._role = 'replica'
        self.assertTrue(self.p.promote())
        self.assertTrue(self.p.promote())

    def test_last_operation(self):
        self.assertEquals(self.p.last_operation(), '0')

    @patch('os.path.isfile', Mock(return_value=True))
    @patch('os.kill', Mock(side_effect=Exception))
    @patch('os.getpid', Mock(return_value=2))
    @patch('os.getppid', Mock(return_value=2))
    @patch.object(builtins, 'open', mock_open(read_data='-1'))
    @patch.object(Postgresql, '_version_file_exists', Mock(return_value=True))
    def test_is_running(self):
        self.assertFalse(self.p.is_running())

    @patch('subprocess.Popen', Mock(side_effect=OSError))
    def test_call_nowait(self):
        self.assertFalse(self.p.call_nowait('on_start'))

    def test_non_existing_callback(self):
        self.assertFalse(self.p.call_nowait('foobar'))

    @patch.object(Postgresql, 'is_running', Mock(return_value=True))
    def test_is_leader_exception(self):
        self.p.start()
        self.p.query = Mock(side_effect=psycopg2.OperationalError("not supported"))
        self.assertTrue(self.p.stop())

    def test_check_replication_lag(self):
        self.assertTrue(self.p.check_replication_lag(0))

    @patch('os.rename', Mock())
    @patch('os.path.isdir', Mock(return_value=True))
    def test_move_data_directory(self):
        self.p.move_data_directory()
        with patch('os.rename', Mock(side_effect=OSError)):
            self.p.move_data_directory()

    @patch.object(Postgresql, 'is_running', Mock(return_value=True))
    def test_bootstrap(self):
        with patch('subprocess.call', Mock(return_value=1)):
            self.assertRaises(PostgresException, self.p.bootstrap, {})

        with patch.object(Postgresql, 'run_bootstrap_post_init', Mock(return_value=False)):
            self.assertRaises(PostgresException, self.p.bootstrap, {})

        self.p.bootstrap({'users': {'replicator': {'password': 'rep-pass', 'options': ['replication']}},
                          'pg_hba': ['host replication replicator 127.0.0.1/32 md5',
                                     'hostssl all all 0.0.0.0/0 md5',
                                     'host all all 0.0.0.0/0 md5'],
                          'post_init': '/bin/false'})
        with open(os.path.join(self.data_dir, 'pg_hba.conf')) as f:
            lines = f.readlines()
            assert 'host replication replicator 127.0.0.1/32 md5\n' in lines
            assert 'host all all 0.0.0.0/0 md5\n' in lines

    def test_run_bootstrap_post_init(self):
        with patch('subprocess.call', Mock(return_value=1)):
            self.assertFalse(self.p.run_bootstrap_post_init({'post_init': '/bin/false'}))

        with patch('subprocess.call', Mock(side_effect=OSError)):
            self.assertFalse(self.p.run_bootstrap_post_init({'post_init': '/bin/false'}))

        with patch('subprocess.call', Mock(return_value=0)) as mock_method:
            self.assertTrue(self.p.run_bootstrap_post_init({'post_init': '/bin/false'}))

        mock_method.assert_called()
        args, kwargs = mock_method.call_args
        assert 'PGPASSFILE' in kwargs['env'].keys()
        self.assertEquals(args[0], ['/bin/false', 'postgres://test@localhost:5432/postgres'])

    @patch('patroni.postgresql.Postgresql.create_replica', Mock(return_value=0))
    def test_clone(self):
        self.p.clone(self.leader)

    @patch('os.listdir', Mock(return_value=['recovery.conf']))
    @patch('os.path.exists', Mock(return_value=True))
    def test_get_postgres_role_from_data_directory(self):
        self.assertEquals(self.p.get_postgres_role_from_data_directory(), 'replica')

    def test_remove_data_directory(self):
        self.p.remove_data_directory()
        open(self.data_dir, 'w').close()
        self.p.remove_data_directory()
        os.symlink('unexisting', self.data_dir)
        with patch('os.unlink', Mock(side_effect=OSError)):
            self.p.remove_data_directory()
        self.p.remove_data_directory()

    @patch('patroni.postgresql.Postgresql._version_file_exists', Mock(return_value=True))
    def test_controldata(self):
        with patch('subprocess.check_output', Mock(return_value=0, side_effect=pg_controldata_string)):
            data = self.p.controldata()
            self.assertEquals(len(data), 50)
            self.assertEquals(data['Database cluster state'], 'shut down in recovery')
            self.assertEquals(data['wal_log_hints setting'], 'on')
            self.assertEquals(int(data['Database block size']), 8192)

        with patch('subprocess.check_output', Mock(side_effect=subprocess.CalledProcessError(1, ''))):
            self.assertEquals(self.p.controldata(), {})

    def test_read_postmaster_opts(self):
        m = mock_open(read_data=postmaster_opts_string())
        with patch.object(builtins, 'open', m):
            data = self.p.read_postmaster_opts()
            self.assertEquals(data['wal_level'], 'hot_standby')
            self.assertEquals(int(data['max_replication_slots']), 5)
            self.assertEqual(data.get('D'), None)

            m.side_effect = IOError
            data = self.p.read_postmaster_opts()
            self.assertEqual(data, dict())

    @patch('subprocess.Popen')
    @patch.object(builtins, 'open', MagicMock(return_value=42))
    def test_single_user_mode(self, subprocess_popen_mock):
        subprocess_popen_mock.return_value.wait.return_value = 0
        self.assertEquals(self.p.single_user_mode(options=dict(archive_mode='on', archive_command='false')), 0)
        subprocess_popen_mock.assert_called_once_with(['postgres', '--single', '-D', self.data_dir,
                                                      '-c', 'archive_command=false', '-c', 'archive_mode=on',
                                                       'postgres'], stdin=subprocess.PIPE,
                                                      stdout=42,
                                                      stderr=subprocess.STDOUT)
        subprocess_popen_mock.reset_mock()
        self.assertEquals(self.p.single_user_mode(command="CHECKPOINT"), 0)
        subprocess_popen_mock.assert_called_once_with(['postgres', '--single', '-D', self.data_dir,
                                                      'postgres'], stdin=subprocess.PIPE,
                                                      stdout=42,
                                                      stderr=subprocess.STDOUT)
        subprocess_popen_mock.return_value = None
        self.assertEquals(self.p.single_user_mode(), 1)

    @patch('os.listdir', MagicMock(side_effect=fake_listdir))
    @patch('os.unlink', return_value=True)
    @patch('os.remove', return_value=True)
    @patch('os.path.islink', return_value=False)
    @patch('os.path.isfile', return_value=True)
    def test_cleanup_archive_status(self, mock_file, mock_link, mock_remove, mock_unlink):
        ap = os.path.join(self.data_dir, 'pg_xlog', 'archive_status/')
        self.p.cleanup_archive_status()
        mock_remove.assert_has_calls([mock.call(ap + 'a'), mock.call(ap + 'b'), mock.call(ap + 'c')])
        mock_unlink.assert_not_called()

        mock_remove.reset_mock()

        mock_file.return_value = False
        mock_link.return_value = True
        self.p.cleanup_archive_status()
        mock_unlink.assert_has_calls([mock.call(ap + 'a'), mock.call(ap + 'b'), mock.call(ap + 'c')])
        mock_remove.assert_not_called()

        mock_unlink.reset_mock()
        mock_remove.reset_mock()

        mock_file.side_effect = OSError
        mock_link.side_effect = OSError
        self.p.cleanup_archive_status()
        mock_unlink.assert_not_called()
        mock_remove.assert_not_called()

    @patch('patroni.postgresql.Postgresql._version_file_exists', Mock(return_value=True))
    @patch('subprocess.check_output', MagicMock(return_value=0, side_effect=pg_controldata_string))
    def test_sysid(self):
        self.assertEqual(self.p.sysid, "6200971513092291716")

    @patch('os.path.isfile', Mock(return_value=True))
    @patch('shutil.copy', Mock(side_effect=IOError))
    def test_save_configuration_files(self):
        self.p.save_configuration_files()

    @patch('os.path.isfile', Mock(side_effect=[False, True]))
    @patch('shutil.copy', Mock(side_effect=IOError))
    def test_restore_configuration_files(self):
        self.p.restore_configuration_files()

    def test_can_create_replica_without_replication_connection(self):
        self.p.config['create_replica_method'] = []
        self.assertFalse(self.p.can_create_replica_without_replication_connection())
        self.p.config['create_replica_method'] = ['wale', 'basebackup']
        self.p.config['wale'] = {'command': 'foo', 'no_master': 1}
        self.assertTrue(self.p.can_create_replica_without_replication_connection())

    def test_replica_method_can_work_without_replication_connection(self):
        self.assertFalse(self.p.replica_method_can_work_without_replication_connection('basebackup'))
        self.assertFalse(self.p.replica_method_can_work_without_replication_connection('foobar'))
        self.p.config['foo'] = {'command': 'bar', 'no_master': 1}
        self.assertTrue(self.p.replica_method_can_work_without_replication_connection('foo'))
        self.p.config['foo'] = {'command': 'bar'}
        self.assertFalse(self.p.replica_method_can_work_without_replication_connection('foo'))

    @patch.object(Postgresql, 'is_running', Mock(return_value=True))
    def test_reload_config(self):
        parameters = self._PARAMETERS.copy()
        parameters.pop('f.oo')
        self.p.reload_config({'retry_timeout': 10, 'listen': '*', 'parameters': parameters})
        parameters['b.ar'] = 'bar'
        self.p.reload_config({'retry_timeout': 10, 'listen': '*', 'parameters': parameters})
        parameters['autovacuum'] = 'on'
        self.p.reload_config({'retry_timeout': 10, 'listen': '*', 'parameters': parameters})
        parameters['autovacuum'] = 'off'
        parameters.pop('search_path')
        self.p.reload_config({'retry_timeout': 10, 'listen': '*:5433', 'parameters': parameters})

    @patch.object(Postgresql, '_version_file_exists', Mock(return_value=True))
    def test_get_major_version(self):
        with patch.object(builtins, 'open', mock_open(read_data='9.4')):
            self.assertEquals(self.p.get_major_version(), 9.4)
        with patch.object(builtins, 'open', Mock(side_effect=Exception)):
            self.assertEquals(self.p.get_major_version(), 0.0)

    def test_postmaster_start_time(self):
        with patch.object(MockCursor, "fetchone", Mock(return_value=('foo', True, '', '', '', '', False))):
            self.assertEqual(self.p.postmaster_start_time(), 'foo')
        with patch.object(MockCursor, "execute", side_effect=psycopg2.Error):
            self.assertIsNone(self.p.postmaster_start_time())