Parallel test execution with py.test

Patch adds ability to execute test run distributed over
several processes, each one with isolated database.

Assumptions:
- nailgun user, requires createdb permission, if not please precreate
  databases in format described below
- postgres database will be used for initial connection
- for environment where createdb can not be granted, like ci
  operator need to create several databases, nailgun[0-7],
  count of databases should be equal to TEST_WORKERS variable
- If no TEST_WORKERS provided - default database name will be used,
  it is almost every time nailgun, but you can overwrite it with
  TEST_NAILGUN_DB env variable

To execute tests on your local environment:
  py.test -n 4 nailgun/tests/

DocImpact
Partial-Bug: 1388751
Change-Id: I6037108f1888b61f971a10db5209b20712467173

nailgun/conftest.py

@@ -0,0 +1,55 @@
+#    Copyright 2014 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 re
+
+from psycopg2 import connect
+
+from nailgun.settings import settings
+
+
+def pytest_addoption(parser):
+    parser.addoption("--dbname", default=settings.DATABASE['name'],
+                     help="Overwrite database name")
+
+
+def pytest_configure(config):
+    db_name = config.getoption('dbname')
+    if hasattr(config, 'slaveinput'):
+        #slaveid have next format gw1
+        #it is internal pytest thing, and we dont want to use it
+        uid = re.search(r'\d+', config.slaveinput['slaveid']).group(0)
+        db_name = '{0}{1}'.format(db_name, uid)
+        connection = connect(
+            dbname='postgres', user=settings.DATABASE['user'],
+            host=settings.DATABASE['host'],
+            password=settings.DATABASE['passwd'])
+        cursor = connection.cursor()
+        if not_present(cursor, db_name):
+            create_database(connection, cursor, db_name)
+    settings.DATABASE['name'] = db_name
+
+
+def create_database(connection, cursor, name):
+    connection.set_isolation_level(0)
+    cursor.execute('create database {0}'.format(name))
+    connection.set_isolation_level(1)
+    cursor.close()
+    connection.close()
+
+
+def not_present(cur, name):
+    cur.execute('select datname from pg_database;')
+    db_list = cur.fetchall()
+    return all([name not in row for row in db_list])

nailgun/test-requirements.txt

@@ -16,3 +16,5 @@ tox==1.7.1
 webtest==2.0.14
 pyprof2calltree==1.3.2
 gprof2dot==2014.09.29
+pytest
+pytest-xdist

nailgun/tox.ini

@@ -9,7 +9,7 @@ install_command = pip install {packages}
 setenv = VIRTUAL_ENV={envdir}
 deps = -r{toxinidir}/test-requirements.txt
 commands =
-    nosetests {posargs:nailgun/test}
+    py.test {posargs:nailgun/test}
 
 [tox:jenkins]
 downloadcache = ~/cache/pip

run_tests.sh

@@ -97,6 +97,7 @@ UI_SERVER_PORT=${UI_SERVER_PORT:-5544}
 FUELCLIENT_SERVER_PORT=${FUELCLIENT_SERVER_PORT:-8003}
 TEST_NAILGUN_DB=${TEST_NAILGUN_DB:-nailgun}
 ARTIFACTS=${ARTIFACTS:-`pwd`/test_run}
+TEST_WORKERS=${TEST_WORKERS:-0}
 mkdir -p $ARTIFACTS
 
 # disabled/enabled flags that are setted from the cli.
@@ -246,11 +247,15 @@ function run_nailgun_tests {
   local result=0
   local artifacts=$ARTIFACTS/nailgun
   local config=$artifacts/test.yaml
+  local options="-vv --junit-xml $NAILGUN_XUNIT"
   prepare_artifacts $artifacts $config
   if [ $# -ne 0 ]; then
     TESTS="$@"
   fi
 
+  if [ ! $TEST_WORKERS -eq 0 ]; then
+    options+=" -n $TEST_WORKERS"
+  fi
   # prepare database
   dropdb $config
   syncdb $config false
@@ -258,7 +263,7 @@ function run_nailgun_tests {
   pushd $ROOT/nailgun >> /dev/null
   # # run tests
   NAILGUN_CONFIG=$config \
-  tox -epy26 -- -vv $testropts $TESTS --xunit-file $NAILGUN_XUNIT || result=1
+  tox -epy26 -- $options $TESTS  || result=1
   popd >> /dev/null
   return $result
 }