set up pytest fixtures and simple cli test

pyproject.toml

@@ -42,6 +42,7 @@ select = [
 [tool.ruff.lint.per-file-ignores]
 # D415: API endpoint docstrings shouldn't end with a period
 "server/controllers/*" = ["D415"]
+"server_tests/*" = ["D"]
 
 [tool.ruff.lint.pydocstyle]
 convention = "google"

server_tests/README.md

@@ -0,0 +1 @@
+Tests for the `server/` folder.

server_tests/conftest.py

@@ -0,0 +1,91 @@
+import os
+from typing import cast
+
+import psycopg2
+import pytest
+from apiflask import APIFlask
+from flask.testing import FlaskClient, FlaskCliRunner
+from psycopg2 import sql
+from psycopg2.extensions import ISOLATION_LEVEL_AUTOCOMMIT
+from sqlalchemy.engine import Engine
+from sqlalchemy.engine.base import Connection
+
+from server import create_app, db
+
+
+@pytest.fixture(scope="session")
+def db_url(db_name="pigeondb_test"):
+    """Creates a test database in postgres, yielding the database URL.
+
+    Drops and recreates the database if it already exists.
+    """
+    conn = psycopg2.connect(
+        dbname="postgres",
+        user="postgres",
+        password="password",
+        host="localhost",
+        port="5432",
+    )
+    conn.set_isolation_level(ISOLATION_LEVEL_AUTOCOMMIT)
+
+    with conn.cursor() as cur:
+        cur.execute(f"SELECT 1 FROM pg_database WHERE datname = '{db_name}'")
+        exists = cur.fetchone()
+        if exists:
+            cur.execute(sql.SQL(f"DROP DATABASE {db_name}"))
+        cur.execute(sql.SQL(f"CREATE DATABASE {db_name}"))
+
+    conn.close()
+
+    yield "postgresql://postgres:password@localhost/ballotdb_test"
+
+
+@pytest.fixture(scope="session")
+def app(db_url: str):
+    os.environ["DATABASE_URL"] = db_url
+
+    app = create_app()
+    app.config.update(
+        {
+            "TESTING": True,
+        }
+    )
+
+    yield app
+
+
+@pytest.fixture(autouse=True)
+def enable_transactional_tests(app: APIFlask):
+    """Enables fast independent tests by rolling back changes made during every test.
+
+    Taken from https://github.com/pallets-eco/flask-sqlalchemy/issues/1171,
+    with modifications for static type checking.
+    """
+
+    with app.app_context():
+        engines = cast(dict[str | None, Engine | Connection], db._app_engines[app])
+
+    engine_cleanup = []
+
+    for key, engine in engines.items():
+        connection = (cast(Engine, engine)).connect()
+        transaction = connection.begin()
+        engines[key] = connection
+        engine_cleanup.append((key, engine, connection, transaction))
+
+    yield
+
+    for key, engine, connection, transaction in engine_cleanup:
+        transaction.rollback()
+        connection.close()
+        engines[key] = engine
+
+
+@pytest.fixture()
+def client(app: APIFlask) -> FlaskClient:
+    return app.test_client()
+
+
+@pytest.fixture()
+def runner(app: APIFlask) -> FlaskCliRunner:
+    return app.test_cli_runner()

server_tests/test_cli.py

@@ -0,0 +1,7 @@
+from click.testing import Result
+
+
+def test_seed_email(runner):
+    result: Result = runner.invoke(args=["seed", "email"])
+    print(result.stdout)
+    assert result.exit_code == 0