Initialise the Auth(entic|oris)ation packages

Initialise the authentication/authorisation system packages and set up the
initial database migrations to set up the system.

* README.md: Add documentation on migrations
* gn3/auth/__init__.py: init package
* gn3/auth/authentication/__init__.py: init package
* gn3/auth/authorisation/__init__.py: init package
* gn3/migrations.py: provide migration utilities
* migrations/auth/20221103_01_js9ub-initialise-the-auth-entic-oris-ation-database.py:
  new migration
* tests/unit/auth/test_init_database.py: test new migration applies and rolls
  back as expected
* tests/unit/conftest.py: fixtures for unit tests
* yoyo.auth.ini: basic configuration for yoyo-migration for auth system
  migrations

1 files changed, 29 insertions, 0 deletions

diff --git a/tests/unit/auth/test_init_database.py b/tests/unit/auth/test_init_database.py
new file mode 100644
index 0000000..bf1ed1d
--- /dev/null
+++ b/tests/unit/auth/test_init_database.py
@@ -0,0 +1,29 @@
+"""Test the auth database initialisation migration."""
+from contextlib import closing
+
+import pytest
+import sqlite3
+
+from gn3.migrations import get_migration, apply_migrations, rollback_migrations
+from tests.unit.conftest import (
+    apply_single_migration, rollback_single_migration)
+
+migration_path = "migrations/auth/20221103_01_js9ub-initialise-the-auth-entic-oris-ation-database.py"
+
+@pytest.mark.unit_test
+def test_initialise_the_database(auth_testdb):
+    with closing(sqlite3.connect(auth_testdb)) as conn, closing(conn.cursor()) as cursor:
+        cursor.execute("SELECT name FROM sqlite_schema WHERE type='table'")
+        result = cursor.fetchall()
+        assert "users" not in [row[0] for row in cursor.fetchall()]
+        apply_single_migration(auth_testdb, get_migration(migration_path))
+        cursor.execute("SELECT name FROM sqlite_schema WHERE type='table'")
+        assert "users" in [row[0] for row in cursor.fetchall()]
+
+@pytest.mark.unit_test
+def test_rollback_initialise_the_database(auth_testdb):
+    with closing(sqlite3.connect(auth_testdb)) as conn, closing(conn.cursor()) as cursor:
+        apply_single_migration(auth_testdb, get_migration(migration_path))
+        rollback_single_migration(auth_testdb, get_migration(migration_path))
+        cursor.execute("SELECT name FROM sqlite_schema WHERE type='table'")
+        assert "users" not in [row[0] for row in cursor.fetchall()]