Adding simple tests for initial routes

tests/test_app.py

@@ -0,0 +1,21 @@
+import pytest
+from litestar.testing import TestClient
+
+from speech_collect.app import app
+
+
+@pytest.fixture
+def client():
+    return TestClient(app=app)
+
+
+def test_index_route(client):
+    resp = client.get("/")
+    assert resp.status_code == 200
+    assert resp.text == "Hello, world!"
+
+
+def test_get_book(client):
+    resp = client.get("/books/1337")
+    assert resp.status_code == 200
+    assert resp.json()["book_id"] == 1337