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_package_keyword.py

@@ -2,44 +2,37 @@ import pytest
 
 from sqlalchemy.exc import IntegrityError
 
-from aurweb.db import create, query
-from aurweb.models.account_type import AccountType
+from aurweb import db
+from aurweb.models.account_type import USER_ID
 from aurweb.models.package_base import PackageBase
 from aurweb.models.package_keyword import PackageKeyword
 from aurweb.models.user import User
-from aurweb.testing import setup_test_db
 
 user = pkgbase = None
 
 
 @pytest.fixture(autouse=True)
-def setup():
+def setup(db_test):
     global user, pkgbase
 
-    setup_test_db("Users", "PackageBases", "PackageKeywords")
-
-    account_type = query(AccountType,
-                         AccountType.AccountType == "User").first()
-    user = create(User, Username="test", Email="test@example.org",
-                  RealName="Test User", Passwd="testPassword",
-                  AccountType=account_type)
-    pkgbase = create(PackageBase,
-                     Name="beautiful-package",
-                     Maintainer=user)
+    with db.begin():
+        user = db.create(User, Username="test", Email="test@example.org",
+                         RealName="Test User", Passwd="testPassword",
+                         AccountTypeID=USER_ID)
+        pkgbase = db.create(PackageBase,
+                            Name="beautiful-package",
+                            Maintainer=user)
 
 
 def test_package_keyword():
-    pkg_keyword = create(PackageKeyword,
-                         PackageBase=pkgbase,
-                         Keyword="test")
+    with db.begin():
+        pkg_keyword = db.create(PackageKeyword,
+                                PackageBase=pkgbase,
+                                Keyword="test")
     assert pkg_keyword in pkgbase.keywords
     assert pkgbase == pkg_keyword.PackageBase
 
 
 def test_package_keyword_null_pkgbase_raises_exception():
-    from aurweb.db import session
-
     with pytest.raises(IntegrityError):
-        create(PackageKeyword,
-               Keyword="test")
-    session.rollback()
+        PackageKeyword(Keyword="test")