Add unit tests

Author: Hisham ElSheshtawy

conftest.py

@@ -1,2 +1,15 @@
 import pytest
-from quart import Quart
+from quart import Quart
+
+
+@pytest.fixture
+def app():
+    app = Quart("testapp")
+    @app.route
+    async def index():
+        return 'hi'
+    return app
+
+@pytest.fixture
+def client(app):
+    return app.test_client()

tests/test_quart_prometheus_logger.py

@@ -1 +1,32 @@
 import pytest
+import pytest_asyncio
+import quart
+
+from quart_prometheus_logger import PrometheusRegistry
+from prometheus_client import REGISTRY
+
+
+def test_init_app(app):
+    registry = PrometheusRegistry()
+    metrics_endpoint = "root"
+    registry.init_app(app, metrics_endpoint)
+    assert "prometheus_error_handler" in app.error_handler_spec
+    assert "prometheus_before_request_callback" in app.before_request_funcs
+    assert "prometheus_after_request_callback" in app.after_request_funcs
+
+
+def test_init(app):
+    registry = PrometheusRegistry(app=app)
+    assert "prometheus_error_handler" in app.error_handler_spec
+    assert "prometheus_before_request_callback" in app.before_request_funcs
+    assert "prometheus_after_request_callback" in app.after_request_funcs
+
+
+@pytest.mark.asyncio
+async def test_customer_labeler(app, client):
+    registry = PrometheusRegistry(app=app)
+    custom_label = lambda _: {"custom_label": 1}
+    registry.custom_route_labeler(custom_label, ["custom_label"])
+    await client.get("/")
+    for _, collector in registry._collectors.items():
+        assert "custom_label" in collector._labelnames