add PackageLicense SQLAlchemy ORM model

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

aurweb/models/package_license.py

+from sqlalchemy.orm import mapper
+
+from aurweb.db import make_relationship
+from aurweb.models.license import License
+from aurweb.models.package import Package
+from aurweb.schema import PackageLicenses
+
+
+class PackageLicense:
+    def __init__(self, Package: Package = None, License: License = None):
+        self.Package = Package
+        self.License = License
+
+
+properties = {
+    "Package": make_relationship(Package,
+                                 PackageLicenses.c.PackageID,
+                                 "package_license",
+                                 uselist=False),
+    "License": make_relationship(License,
+                                 PackageLicenses.c.LicenseID,
+                                 "package_license",
+                                 uselist=False)
+}
+
+mapper(PackageLicense, PackageLicenses, properties=properties,
+       primary_key=[PackageLicenses.c.PackageID, PackageLicenses.c.LicenseID])

test/test_package_license.py

+import pytest
+
+from sqlalchemy.exc import IntegrityError
+
+from aurweb.db import create, query
+from aurweb.models.account_type import AccountType
+from aurweb.models.license import License
+from aurweb.models.package import Package
+from aurweb.models.package_base import PackageBase
+from aurweb.models.package_license import PackageLicense
+from aurweb.models.user import User
+from aurweb.testing import setup_test_db
+
+user = license = pkgbase = package = None
+
+
+@pytest.fixture(autouse=True)
+def setup():
+    global user, license, pkgbase, package
+
+    setup_test_db("Users", "PackageBases", "Packages",
+                  "Licenses", "PackageLicenses")
+
+    account_type = query(AccountType,
+                         AccountType.AccountType == "User").first()
+    user = create(User, Username="test", Email="test@example.org",
+                  RealName="Test User", Passwd="testPassword",
+                  account_type=account_type)
+
+    license = create(License, Name="Test License")
+    pkgbase = create(PackageBase, Name="test-package", Maintainer=user)
+    package = create(Package, PackageBase=pkgbase, Name=pkgbase.Name)
+
+
+def test_package_license():
+    package_license = create(PackageLicense, Package=package, License=license)
+    assert package_license.License == license
+    assert package_license.Package == package
+
+
+def test_package_license_null_package_raises_exception():
+    from aurweb.db import session
+    with pytest.raises(IntegrityError):
+        create(PackageLicense, License=license)
+    session.rollback()
+
+
+def test_package_license_null_license_raises_exception():
+    from aurweb.db import session
+    with pytest.raises(IntegrityError):
+        create(PackageLicense, Package=package)
+    session.rollback()