Some more tests for mongodb code (#1036)

* Some more tests for mongodb code

Cleanup connection code

* pep8 fixes

bigchaindb/backend/mongodb/connection.py

@@ -36,11 +36,7 @@ class MongoDBConnection(Connection):
 
     @property
     def db(self):
-        if self.conn is None:
-            self._connect()
-
-        else:
-            return self.conn[self.dbname]
+        return self.conn[self.dbname]
 
     def _connect(self):
         for i in range(self.max_tries):

tests/backend/mongodb/test_connection.py

@@ -1,3 +1,8 @@
+from unittest import mock
+
+import pytest
+from pymongo.errors import ConnectionFailure
+
 
 def test_get_connection_returns_the_correct_instance():
     from bigchaindb.backend import connect
@@ -14,3 +19,20 @@ def test_get_connection_returns_the_correct_instance():
     conn = connect(**config)
     assert isinstance(conn, Connection)
     assert isinstance(conn, MongoDBConnection)
+
+
+@mock.patch('pymongo.MongoClient.__init__')
+@mock.patch('time.sleep')
+def test_connection_error(mock_sleep, mock_client):
+    from bigchaindb.backend import connect
+
+    # force the driver to trow ConnectionFailure
+    # the mock on time.sleep is to prevent the actual sleep when running
+    # the tests
+    mock_client.side_effect = ConnectionFailure()
+
+    with pytest.raises(ConnectionFailure):
+        conn = connect()
+        conn.db
+
+    assert mock_client.call_count == 3

tests/backend/mongodb/test_schema.py

@@ -1,5 +1,9 @@
+from unittest import mock
+
 import pytest
-from unittest.mock import patch
+from pymongo.database import Database
+from pymongo.errors import OperationFailure
+
 
 pytestmark = pytest.mark.bdb
 
@@ -105,7 +109,6 @@ def test_drop(dummy_db):
 
 
 def test_get_replica_set_name_not_enabled():
-    from pymongo.database import Database
     from bigchaindb import backend
     from bigchaindb.backend.mongodb.schema import _get_replica_set_name
     from bigchaindb.common.exceptions import ConfigurationError
@@ -116,13 +119,12 @@ def test_get_replica_set_name_not_enabled():
     cmd_line_opts = {'argv': ['mongod', '--dbpath=/data'],
                      'ok': 1.0,
                      'parsed': {'storage': {'dbPath': '/data'}}}
-    with patch.object(Database, 'command', return_value=cmd_line_opts):
+    with mock.patch.object(Database, 'command', return_value=cmd_line_opts):
         with pytest.raises(ConfigurationError):
             _get_replica_set_name(conn)
 
 
 def test_get_replica_set_name_command_line():
-    from pymongo.database import Database
     from bigchaindb import backend
     from bigchaindb.backend.mongodb.schema import _get_replica_set_name
 
@@ -133,12 +135,11 @@ def test_get_replica_set_name_command_line():
                      'ok': 1.0,
                      'parsed': {'replication': {'replSet': 'rs0'},
                                 'storage': {'dbPath': '/data'}}}
-    with patch.object(Database, 'command', return_value=cmd_line_opts):
+    with mock.patch.object(Database, 'command', return_value=cmd_line_opts):
         assert _get_replica_set_name(conn) == 'rs0'
 
 
 def test_get_replica_set_name_config_file():
-    from pymongo.database import Database
     from bigchaindb import backend
     from bigchaindb.backend.mongodb.schema import _get_replica_set_name
 
@@ -149,5 +150,46 @@ def test_get_replica_set_name_config_file():
                      'ok': 1.0,
                      'parsed': {'replication': {'replSetName': 'rs0'},
                                 'storage': {'dbPath': '/data'}}}
-    with patch.object(Database, 'command', return_value=cmd_line_opts):
+    with mock.patch.object(Database, 'command', return_value=cmd_line_opts):
         assert _get_replica_set_name(conn) == 'rs0'
+
+
+def test_wait_for_replica_set_initialization():
+    from bigchaindb.backend.mongodb.schema import _wait_for_replica_set_initialization  # noqa
+    from bigchaindb.backend import connect
+    conn = connect()
+
+    with mock.patch.object(Database, 'command') as mock_command:
+        mock_command.side_effect = [
+            {'log': ['a line']},
+            {'log': ['database writes are now permitted']},
+        ]
+
+        # check that it returns
+        assert _wait_for_replica_set_initialization(conn) is None
+
+
+def test_initialize_replica_set():
+    from bigchaindb.backend.mongodb.schema import initialize_replica_set
+    from bigchaindb.backend import connect
+    conn = connect()
+
+    with mock.patch.object(Database, 'command') as mock_command:
+        mock_command.side_effect = [
+            mock.DEFAULT,
+            None,
+            {'log': ['database writes are now permitted']},
+        ]
+
+        # check that it returns
+        assert initialize_replica_set(conn) is None
+
+    # test it raises OperationError if anything wrong
+    with mock.patch.object(Database, 'command') as mock_command:
+        mock_command.side_effect = [
+            mock.DEFAULT,
+            OperationFailure(None, details={'codeName': ''})
+        ]
+
+        with pytest.raises(OperationFailure):
+            initialize_replica_set(conn)