tests: introduce REUSE_TEST_DB as an alternative to TEST_DB

With TEST_DB, the specified database would be dropped (if existing) and created
from scratch. That would fail if the user only had been granted access to that
database without general database creation permissions.

With REUSE_TEST_DB, the database must exist, and the tables in the existing
database will be deleted before creating the new ones.

This is for example useful for testing on PostgreSQL without full database
privileges. (With MariaDB/MySQL, it is possible to grant create permissions to
a database before it exists, so it is easier to use TEST_DB.)

docs/contributing.rst

@@ -92,6 +92,17 b' Note that on unix systems, the temporary'
 and the test suite creates repositories in the temporary directory. Linux
 systems with /tmp mounted noexec will thus fail.
 
+Tests can be run on PostgreSQL like::
+
+    sudo -u postgres createuser 'kallithea-test' --pwprompt  # password password
+    sudo -u postgres createdb 'kallithea-test' --owner 'kallithea-test'
+    REUSE_TEST_DB='postgresql://kallithea-test:password@localhost/kallithea-test' py.test
+
+Tests can be run on MariaDB/MySQL like::
+
+    echo "GRANT ALL PRIVILEGES ON \`kallithea-test\`.* TO 'kallithea-test'@'localhost' IDENTIFIED BY 'password'" | sudo -u mysql mysql
+    TEST_DB='mysql://kallithea-test:password@localhost/kallithea-test?charset=utf8' py.test
+
 You can also use ``tox`` to run the tests with all supported Python versions.
 
 When running tests, Kallithea generates a `test.ini` based on template values

kallithea/tests/conftest.py

@@ -59,8 +59,12 b' def pytest_configure():'
             'formatter': 'color_formatter_sql',
         },
     }
-    if os.environ.get('TEST_DB'):
-        ini_settings['[app:main]']['sqlalchemy.url'] = os.environ.get('TEST_DB')
+    create_database = os.environ.get('TEST_DB')  # TODO: rename to 'CREATE_TEST_DB'
+    if create_database:
+        ini_settings['[app:main]']['sqlalchemy.url'] = create_database
+    reuse_database = os.environ.get('REUSE_TEST_DB')
+    if reuse_database:
+        ini_settings['[app:main]']['sqlalchemy.url'] = reuse_database
 
     test_ini_file = os.path.join(TESTS_TMP_PATH, 'test.ini')
     inifile.create(test_ini_file, None, ini_settings)
@@ -70,7 +74,7 b' def pytest_configure():'
 
     # set KALLITHEA_NO_TMP_PATH=1 to disable re-creating the database and test repos
     if not int(os.environ.get('KALLITHEA_NO_TMP_PATH', 0)):
-        create_test_env(TESTS_TMP_PATH, context.config())
+        create_test_env(TESTS_TMP_PATH, context.config(), reuse_database=bool(reuse_database))
 
     # set KALLITHEA_WHOOSH_TEST_DISABLE=1 to disable whoosh index during tests
     if not int(os.environ.get('KALLITHEA_WHOOSH_TEST_DISABLE', 0)):

kallithea/tests/fixture.py

@@ -349,7 +349,7 b' class Fixture(object):'
 # Global test environment setup
 #==============================================================================
 
-def create_test_env(repos_test_path, config):
+def create_test_env(repos_test_path, config, reuse_database):
     """
     Makes a fresh database and
     install test repository into tmp dir
@@ -366,7 +366,7 b' def create_test_env(repos_test_path, con'
 
     dbmanage = DbManage(dbconf=dbconf, root=config['here'],
                         tests=True)
-    dbmanage.create_tables()
+    dbmanage.create_tables(reuse_database=reuse_database)
     # for tests dynamically set new root paths based on generated content
     dbmanage.create_settings(dbmanage.prompt_repo_root_path(repos_test_path))
     dbmanage.create_default_user()