def test_conn(self, stub_connect):
"""Property lazily instantiates a connection object.
After creating a connection, the session is set to readonly
and autocommit to avoid issues with hanging transactions (only
SELECT is used; we don't want to modify the static data).
Note: the conn property also prompts for a password on
creating a new connection if it hasn't been provided in the
config but this isn't tested here.
"""
database = db.Database()
self.assertFalse(stub_connect.called)
value = database.conn
# Check the DBAPI has been invoked correctly
expected_parameters = {
'cursor_factory': database.default_cursor_factory
}
expected_parameters.update(database.conn_details)
stub_connect.assert_called_once_with(**expected_parameters)
# Check the object return by the connect attempt is used.
mock_connection = stub_connect.return_value
mock_connection.set_session.assert_called_once_with(autocommit=True,
readonly=True)
self.assertIs(value, mock_connection)
def test_conn_details(self):
"""Property contains connection details for the database.
The connection details are sourced from the config file(s)
located in the usual app dirs (dependent on OS).
"""
database = db.Database()
self.assertEqual(database.conn_details['host'], 'localhost')
def test_tables(self, stub_property):
"""Property is a list of tables taken from the schema dict."""
dummy_schema = {
'table1': ['columnA', 'columnB'],
'table2': ['columnC', 'columnD'],
}
stub_property.return_value = dummy_schema
database = db.Database()
self.assertCountEqual(database.tables, dummy_schema.keys())
def test_default_cursor_factory(self, stub_property):
"""Property handles setting connection's cursor factory.
The setter assigns the new value to the internal attribute on
the class and the `cursor_factory` attribute of the connection
stored in the `conn` property.
"""
database = db.Database()
database.default_cursor_factory = 'foo'
self.assertEqual(database.default_cursor_factory, 'foo')
self.assertEqual(stub_property.return_value.cursor_factory, 'foo')
def test_schema(self, stub_query):
"""Property is a dict of tables and columns."""
mock_cursor = stub_query.return_value
mock_cursor.fetchall.return_value = [
('table1', 'columnA', 1),
('table1', 'columnB', 2),
('table2', 'columnC', 1),
('table2', 'columnD', 2),
]
database = db.Database()
self.assertEqual(database.schema, {
'table1': ['columnA', 'columnB'],
'table2': ['columnC', 'columnD']
})
def test_query(self, stub_property):
"""Method wraps psycopg2's DBAPI compatible execute method."""
database = db.Database()
# Reference the mock connection and expected execute args
mock_connection = stub_property.return_value
args, kwargs = ('sql statement', 'foo'), dict(kw='bar')
# Invoke
cursor = database.query(*args, cursor_factory='baz', **kwargs)
# Check the connection/cursor is used properly.
mock_connection.cursor.assert_called_once_with(cursor_factory='baz')
self.assertIs(cursor, mock_connection.cursor.return_value)
cursor.execute.assert_called_once_with(*args, **kwargs)