test: add model integration and threshold tests

tests/test_model.py

@@ -0,0 +1,66 @@
+import pytest
+from unittest.mock import MagicMock, patch
+from fastapi.testclient import TestClient
+
+from ml_model.loader import load_pipeline
+from app.main import app
+from tests.conftest import VALID_PAYLOAD, TEST_API_KEY
+
+
+# Fixture : client avec le VRAI pipeline (pas de mock)
+@pytest.fixture(scope="module")
+def real_client():
+    with patch.dict("os.environ", {"API_KEY": TEST_API_KEY}):
+        with TestClient(app) as c:
+            yield c
+
+
+# Tester que le pipeline .pkl se charge correctement
+def test_load_pipeline():
+    pipeline, threshold = load_pipeline()
+    assert pipeline is not None
+    assert isinstance(threshold, float)
+
+
+# Tester que la prédiction retourne bien "Reste" ou "Quitte"
+def test_predict_label_valid(real_client):
+    response = real_client.post(
+        "/predict",
+        json=VALID_PAYLOAD,
+        headers={"X-API-Key": TEST_API_KEY},
+    )
+    assert response.status_code == 200
+    assert response.json()["label"] in ("Reste", "Quitte")
+
+
+# Tester que la probabilité est bien comprise entre 0 et 1
+def test_predict_probabilite_range(real_client):
+    response = real_client.post(
+        "/predict",
+        json=VALID_PAYLOAD,
+        headers={"X-API-Key": TEST_API_KEY},
+    )
+    assert 0.0 <= response.json()["probabilite"] <= 1.0
+
+
+# Tester que le seuil 0.40 est bien appliqué
+@pytest.mark.parametrize("proba_quitte,expected_label", [
+    (0.50, "Quitte"),  # clairement au-dessus du seuil
+    (0.30, "Reste"),   # clairement en-dessous du seuil
+])
+def test_threshold_applied(proba_quitte, expected_label):
+    _, threshold = load_pipeline()  # ← vrai seuil (0.3999...7)
+    mock_pipeline = MagicMock()
+    mock_pipeline.predict_proba.return_value = [[1 - proba_quitte, proba_quitte]]
+
+    with patch("app.main.load_pipeline", return_value=(mock_pipeline, threshold)), \
+         patch.dict("os.environ", {"API_KEY": TEST_API_KEY}):
+        with TestClient(app) as c:
+            response = c.post(
+                "/predict",
+                json=VALID_PAYLOAD,
+                headers={"X-API-Key": TEST_API_KEY},
+            )
+
+    assert response.json()["label"] == expected_label
+