Use isolated filebased sqlite for each test process

Changed configuration of testr to use file based sqlite database.
Database name will be finally configured in solar/conftest.py
for each process.
If --clean flag will be provided to py.test - database will be removed
after testrun.

All dblayer patches were removed from solar/__init__.py to
solar/dblayer/__init__.py to avoid patching of sqlite client

Change-Id: I615be46aecbb0b88a1088f5a379f10ba95ae9aad

.testr.conf

@@ -1,5 +1,5 @@
 [DEFAULT]
-test_command=SOLAR_DB=${SOLAR_DB:=sqlite://} \
-             py.test ./solar --subunit $LISTOPT $IDOPTION
+test_command=SOLAR_DB=${SOLAR_DB:='sqlite:////tmp/solar_{PID}.db'} \
+             py.test --clean ./solar --subunit $LISTOPT $IDOPTION
 test_id_option=--subunit-load-list=$IDFILE
 test_list_option=--collectonly

solar/__init__.py

@@ -4,5 +4,3 @@ except ImportError:
     pass
 else:
     monkey.patch_all()
-    from solar.dblayer.gevent_patches import patch_all
-    patch_all()

solar/conftest.py

@@ -0,0 +1,34 @@
+#    Copyright 2015 Mirantis, Inc.
+#
+#    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.
+
+import os
+
+from solar.config import C
+from solar import utils
+
+
+C.solar_db = C.solar_db.format(PID=os.getpid())
+
+
+def pytest_addoption(parser):
+    parser.addoption(
+        "--clean", action="store_true", default=False,
+        help="Use this option for additional cleanup")
+
+
+def pytest_unconfigure(config):
+    if config.getoption("clean"):
+        db, opts = utils.parse_database_conn(C.solar_db)
+        if db.mode == 'sqlite' and os.path.isfile(db.database):
+            os.unlink(db.database)

solar/dblayer/__init__.py

@@ -1,3 +1,11 @@
+try:
+    from gevent import monkey
+except ImportError:
+    pass
+else:
+    from solar.dblayer.gevent_patches import patch_all
+    patch_all()
+
 from solar.dblayer.model import ModelMeta
 from solar.config import C
 from solar.utils import parse_database_conn