feat: endpoint /health avec tests (8 tests)

Ajoute GET /health retournant un JSON avec :
- status: "ok"
- version: "2.1.0"
- ollama: true/false (connectivité testée avec timeout 2s)
- timestamp: ISO 8601 UTC

Tests couvrent : format JSON, champs requis, Ollama joignable/injoignable,
format timestamp ISO, type booléen du champ ollama.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/viewer/app.py

@@ -616,4 +616,21 @@ def create_app() -> Flask:
                                metrics=metrics, total_selection=len(selection),
                                groups=groups)
 
+    # --- Health check endpoint ---
+    @app.route("/health")
+    def health():
+        from datetime import datetime, timezone
+        ollama_ok = False
+        try:
+            r = requests.get(f"{OLLAMA_URL}/api/tags", timeout=2)
+            ollama_ok = r.status_code == 200
+        except Exception:
+            pass
+        return jsonify({
+            "status": "ok",
+            "version": "2.1.0",
+            "ollama": ollama_ok,
+            "timestamp": datetime.now(timezone.utc).isoformat(),
+        })
+
     return app

tests/test_health_endpoint.py

@@ -0,0 +1,79 @@
+"""Tests pour le endpoint /health du viewer Flask."""
+
+import json
+import os
+from unittest.mock import patch, MagicMock
+
+import pytest
+import requests
+
+from src.viewer.app import create_app
+
+
+@pytest.fixture
+def app():
+    with patch.dict(os.environ, {"T2A_DEMO_USER": "", "T2A_DEMO_PASS": ""}):
+        app = create_app()
+        app.config["TESTING"] = True
+        yield app
+
+
+@pytest.fixture
+def client(app):
+    return app.test_client()
+
+
+class TestHealthEndpoint:
+
+    def test_health_returns_200(self, client):
+        response = client.get("/health")
+        assert response.status_code == 200
+
+    def test_health_returns_json(self, client):
+        response = client.get("/health")
+        data = response.get_json()
+        assert data is not None
+        assert data["status"] == "ok"
+
+    def test_health_contains_required_fields(self, client):
+        response = client.get("/health")
+        data = response.get_json()
+        assert "status" in data
+        assert "version" in data
+        assert "ollama" in data
+        assert "timestamp" in data
+
+    def test_health_version_format(self, client):
+        response = client.get("/health")
+        data = response.get_json()
+        assert data["version"] == "2.1.0"
+
+    def test_health_timestamp_is_iso(self, client):
+        from datetime import datetime
+        response = client.get("/health")
+        data = response.get_json()
+        # Should parse without error
+        ts = datetime.fromisoformat(data["timestamp"])
+        assert ts is not None
+
+    @patch("src.viewer.app.requests.get")
+    def test_health_ollama_reachable(self, mock_get, client):
+        """Quand Ollama répond, ollama=True."""
+        mock_resp = MagicMock()
+        mock_resp.status_code = 200
+        mock_get.return_value = mock_resp
+        response = client.get("/health")
+        data = response.get_json()
+        assert data["ollama"] is True
+
+    @patch("src.viewer.app.requests.get", side_effect=requests.ConnectionError("refused"))
+    def test_health_ollama_unreachable(self, mock_get, client):
+        """Quand Ollama est injoignable, ollama=False."""
+        response = client.get("/health")
+        data = response.get_json()
+        assert data["ollama"] is False
+
+    def test_health_ollama_is_bool(self, client):
+        response = client.get("/health")
+        data = response.get_json()
+        assert isinstance(data["ollama"], bool)