add PackageNotification SQLAlchemy ORM model

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

aurweb/models/package_notification.py

+from sqlalchemy import Column, ForeignKey, Integer
+from sqlalchemy.exc import IntegrityError
+from sqlalchemy.orm import backref, relationship
+
+import aurweb.models.package_base
+import aurweb.models.user
+
+from aurweb.models.declarative import Base
+
+
+class PackageNotification(Base):
+    __tablename__ = "PackageNotifications"
+
+    UserID = Column(
+        Integer, ForeignKey("Users.ID", ondelete="CASCADE"),
+        nullable=False)
+    User = relationship(
+        "User", backref=backref("package_notifications", lazy="dynamic"),
+        foreign_keys=[UserID])
+
+    PackageBaseID = Column(
+        Integer, ForeignKey("PackageBases.ID", ondelete="CASCADE"),
+        nullable=False)
+    PackageBase = relationship(
+        "PackageBase",
+        backref=backref("package_notifications", lazy="dynamic"),
+        foreign_keys=[PackageBaseID])
+
+    __mapper_args__ = {"primary_key": [UserID, PackageBaseID]}
+
+    def __init__(self,
+                 User: aurweb.models.user.User = None,
+                 PackageBase: aurweb.models.package_base.PackageBase = None,
+                 NotificationTS: int = None):
+        self.User = User
+        if not self.User:
+            raise IntegrityError(
+                statement="Foreign key UserID cannot be null.",
+                orig="PackageNotifications.UserID",
+                params=("NULL"))
+
+        self.PackageBase = PackageBase
+        if not self.PackageBase:
+            raise IntegrityError(
+                statement="Foreign key PackageBaseID cannot be null.",
+                orig="PackageNotifications.PackageBaseID",
+                params=("NULL"))

test/test_package_notification.py

+import pytest
+
+from sqlalchemy.exc import IntegrityError
+
+from aurweb.db import create, rollback
+from aurweb.models.package_base import PackageBase
+from aurweb.models.package_notification import PackageNotification
+from aurweb.models.user import User
+from aurweb.testing import setup_test_db
+
+user = pkgbase = None
+
+
+@pytest.fixture(autouse=True)
+def setup():
+    global user, pkgbase
+
+    setup_test_db("Users", "PackageBases", "PackageNotifications")
+
+    user = create(User, Username="test", Email="test@example.org",
+                  RealName="Test User", Passwd="testPassword")
+    pkgbase = create(PackageBase, Name="test-package", Maintainer=user)
+
+
+def test_package_notification_creation():
+    package_notification = create(PackageNotification, User=user,
+                                  PackageBase=pkgbase)
+    assert bool(package_notification)
+    assert package_notification.User == user
+    assert package_notification.PackageBase == pkgbase
+
+
+def test_package_notification_null_user_raises_exception():
+    with pytest.raises(IntegrityError):
+        create(PackageNotification, PackageBase=pkgbase)
+    rollback()
+
+
+def test_package_notification_null_pkgbase_raises_exception():
+    with pytest.raises(IntegrityError):
+        create(PackageNotification, User=user)
+    rollback()