change(aurweb): add parallel tests and improve aurweb.db

This change utilizes pytest-xdist to perform a multiproc test
run and reworks aurweb.db's code. We no longer use a global
engine, session or Session, but we now use a memo of engines
and sessions as they are requested, based on the PYTEST_CURRENT_TEST
environment variable, which is available during testing.

Additionally, this change strips several SQLite components
out of the Python code-base.

SQLite is still compatible with PHP and sharness tests, but
not with our FastAPI implementation.

More changes:
------------
- Remove use of aurweb.db.session global in other code.
- Use new aurweb.db.name() dynamic db name function in env.py.
- Added 'addopts' to pytest.ini which utilizes multiprocessing.
    - Highly recommended to leave this be or modify `-n auto` to
      `-n {cpu_threads}` where cpu_threads is at least 2.

Signed-off-by: Kevin Morris <kevr@0cost.org>

test/test_ratelimit.py

@@ -8,15 +8,14 @@ from aurweb import config, db, logging
 from aurweb.models import ApiRateLimit
 from aurweb.ratelimit import check_ratelimit
 from aurweb.redis import redis_connection
-from aurweb.testing import setup_test_db
 from aurweb.testing.requests import Request
 
 logger = logging.get_logger(__name__)
 
 
 @pytest.fixture(autouse=True)
-def setup():
-    setup_test_db(ApiRateLimit.__tablename__)
+def setup(db_test):
+    return
 
 
 @pytest.fixture
@@ -31,27 +30,36 @@ def pipeline():
     yield pipeline
 
 
+config_getint = config.getint
+
+
 def mock_config_getint(section: str, key: str):
     if key == "request_limit":
         return 4
     elif key == "window_length":
         return 100
-    return config.getint(section, key)
+    return config_getint(section, key)
+
+
+config_getboolean = config.getboolean
 
 
 def mock_config_getboolean(return_value: int = 0):
     def fn(section: str, key: str):
         if section == "ratelimit" and key == "cache":
             return return_value
-        return config.getboolean(section, key)
+        return config_getboolean(section, key)
     return fn
 
 
+config_get = config.get
+
+
 def mock_config_get(return_value: str = "none"):
     def fn(section: str, key: str):
         if section == "options" and key == "cache":
             return return_value
-        return config.get(section, key)
+        return config_get(section, key)
     return fn