Unit tests for FastAPI branch

Run via `make test`

tests/conftest.py

@@ -1,12 +1,28 @@
+import asyncio
 import pytest
-
+from httpx import AsyncClient
 from lnbits.app import create_app
+from lnbits.commands import migrate_databases
+from lnbits.settings import HOST, PORT
+import tests.mocks
 
+# use session scope to run once before and once after all tests
+@pytest.fixture(scope="session")
+def app():
+    # yield and pass the app to the test
+    app = create_app()
+    loop = asyncio.get_event_loop()
+    loop.run_until_complete(migrate_databases())
+    yield app
+    # get the current event loop and gracefully stop any running tasks
+    loop = asyncio.get_event_loop()
+    loop.run_until_complete(loop.shutdown_asyncgens())
+    loop.close()
 
 @pytest.fixture
-async def client():
-    app = create_app()
-    app.config["TESTING"] = True
-
-    async with app.test_client() as client:
-        yield client
+async def client(app):
+    client = AsyncClient(app=app, base_url=f'http://{HOST}:{PORT}')
+    # yield and pass the client to the test
+    yield client
+    # close the async client after the test has finished
+    await client.aclose()