fix: prevent source state writes in dry-run

tests/unit/test_pronote_auth_state.py

@@ -37,6 +37,90 @@ def test_load_no_file_returns_none(tmp_path: Path) -> None:
     assert state.load() is None
 
 
+def test_disabled_persistence_keeps_credentials_in_memory_without_creating_file(
+    tmp_path: Path,
+) -> None:
+    """Vérifie que la persistance désactivée conserve les credentials en mémoire.
+
+    :param tmp_path: Fixture pytest pour un répertoire temporaire.
+    :return: None
+    """
+    state_file = tmp_path / "auth.json"
+    credentials = {
+        "pronote_url": "https://example.com/pronote",
+        "username": "parent-1",
+        "password": "token-123",  # pragma: allowlist secret
+        "uuid": "uuid-456",
+    }
+    state = PronoteAuthState(state_file, persistence_enabled=False)
+
+    state.save(credentials)
+
+    assert state.load() == credentials
+    assert not state_file.exists()
+
+
+def test_disabled_persistence_preserves_existing_file(tmp_path: Path) -> None:
+    """Vérifie que la persistance désactivée garde les nouveaux credentials en mémoire.
+
+    :param tmp_path: Fixture pytest pour un répertoire temporaire.
+    :return: None
+    """
+    state_file = tmp_path / "auth.json"
+    original_credentials = {
+        "pronote_url": "https://example.com/pronote",
+        "username": "parent-1",
+        "password": "old-token",  # pragma: allowlist secret
+        "uuid": "old-uuid",
+    }
+    original_content = json.dumps({"version": 1, "credentials": original_credentials}).encode()
+    new_credentials = {
+        "pronote_url": "https://example.com/pronote",
+        "username": "parent-1",
+        "password": "new-token",  # pragma: allowlist secret
+        "uuid": "new-uuid",
+    }
+    state_file.write_bytes(original_content)
+    state = PronoteAuthState(state_file, persistence_enabled=False)
+
+    assert state.load() == original_credentials
+
+    state.save(new_credentials)
+
+    assert state.load() == new_credentials
+    assert state_file.read_bytes() == original_content
+
+
+def test_disabled_persistence_clear_discards_in_memory_credentials_only(tmp_path: Path) -> None:
+    """Vérifie que clear oublie l'état en mémoire sans modifier le fichier existant.
+
+    :param tmp_path: Fixture pytest pour un répertoire temporaire.
+    :return: None
+    """
+    state_file = tmp_path / "auth.json"
+    original_credentials = {
+        "pronote_url": "https://example.com/pronote",
+        "username": "parent-1",
+        "password": "old-token",  # pragma: allowlist secret
+        "uuid": "old-uuid",
+    }
+    original_content = json.dumps({"version": 1, "credentials": original_credentials}).encode()
+    credentials = {
+        "pronote_url": "https://example.com/pronote",
+        "username": "parent-1",
+        "password": "new-token",  # pragma: allowlist secret
+        "uuid": "new-uuid",
+    }
+    state_file.write_bytes(original_content)
+    state = PronoteAuthState(state_file, persistence_enabled=False)
+
+    state.save(credentials)
+    state.clear()
+
+    assert state.load() is None
+    assert state_file.read_bytes() == original_content
+
+
 def test_save_then_load_roundtrip(tmp_path: Path) -> None:
     """Vérifie que des credentials sauvegardés sont rechargés à l'identique.