Test suite executed from CI pipeline (#433)

* Test strategy & test cases

* Unit tests

* Integration tests

tests/unit/test_gateway/test_endpoint_metrics.py

@@ -0,0 +1,60 @@
+"""
+Tests for Gateway Metrics Endpoint
+"""
+
+import pytest
+from unittest.mock import MagicMock
+
+from trustgraph.gateway.endpoint.metrics import MetricsEndpoint
+
+
+class TestMetricsEndpoint:
+    """Test cases for MetricsEndpoint class"""
+
+    def test_metrics_endpoint_initialization(self):
+        """Test MetricsEndpoint initialization"""
+        mock_auth = MagicMock()
+        
+        endpoint = MetricsEndpoint(
+            prometheus_url="http://prometheus:9090",
+            endpoint_path="/metrics",
+            auth=mock_auth
+        )
+        
+        assert endpoint.prometheus_url == "http://prometheus:9090"
+        assert endpoint.path == "/metrics"
+        assert endpoint.auth == mock_auth
+        assert endpoint.operation == "service"
+
+    @pytest.mark.asyncio
+    async def test_metrics_endpoint_start_method(self):
+        """Test MetricsEndpoint start method (should be no-op)"""
+        mock_auth = MagicMock()
+        
+        endpoint = MetricsEndpoint(
+            prometheus_url="http://localhost:9090",
+            endpoint_path="/metrics",
+            auth=mock_auth
+        )
+        
+        # start() should complete without error
+        await endpoint.start()
+
+    def test_add_routes_registers_get_handler(self):
+        """Test add_routes method registers GET route with wildcard path"""
+        mock_auth = MagicMock()
+        mock_app = MagicMock()
+        
+        endpoint = MetricsEndpoint(
+            prometheus_url="http://prometheus:9090",
+            endpoint_path="/metrics",
+            auth=mock_auth
+        )
+        
+        endpoint.add_routes(mock_app)
+        
+        # Verify add_routes was called with GET route
+        mock_app.add_routes.assert_called_once()
+        # The call should include web.get with wildcard path pattern
+        call_args = mock_app.add_routes.call_args[0][0]
+        assert len(call_args) == 1  # One route added