fix(client): address PR #67 review — error propagation, test cleanup

SessionManager.new_game() now returns "" on dir creation failure
instead of proceeding with a broken game-id. Main menu guards
against empty return. Test suite tracks and cleans up created
save directories in after_test().

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

client/scripts/autoloads/session_manager.gd

@@ -30,6 +30,7 @@ func new_game() -> String:
 	if err != OK:
 		push_error("SessionManager: failed to create save dir %s: %s" % [
 			save_path, error_string(err)])
+		return ""
 	GameState.current_game_id = game_id
 	return game_id
 
@@ -74,7 +75,6 @@ func quit_to_menu(node: Node) -> void:
 	if _quit_dialog != null and is_instance_valid(_quit_dialog):
 		return  # Dialog already open
 	_quit_dialog = ConfirmationDialog.new()
-	_quit_dialog.title = ""
 	_quit_dialog.dialog_text = UIStrings.get_text("menu.confirm_quit")
 	_quit_dialog.ok_button_text = UIStrings.get_text("menu.confirm_yes")
 	_quit_dialog.cancel_button_text = UIStrings.get_text("menu.confirm_no")

client/tests/test_session_manager_sprint19.gd

@@ -4,6 +4,9 @@
 class_name TestSessionManagerSprint19
 extends GdUnitTestSuite
 
+# Game IDs created during the current test — deleted in after_test().
+var _created_ids: Array = []
+
 
 # ---------------------------------------------------------------------------
 # Lifecycle
@@ -11,12 +14,28 @@ extends GdUnitTestSuite
 
 func before_test() -> void:
 	GameState.current_game_id = ""
+	_created_ids = []
 
 
 func after_test() -> void:
+	for game_id in _created_ids:
+		var path := "user://saves/" + game_id
+		DirAccess.remove_absolute(ProjectSettings.globalize_path(path))
+	_created_ids.clear()
 	GameState.current_game_id = ""
 
 
+# ---------------------------------------------------------------------------
+# Helper: call new_game() and track the created directory for cleanup.
+# ---------------------------------------------------------------------------
+
+func _new_game() -> String:
+	var game_id := SessionManager.new_game()
+	if not game_id.is_empty():
+		_created_ids.append(game_id)
+	return game_id
+
+
 # ---------------------------------------------------------------------------
 # GameState.current_game_id field
 # ---------------------------------------------------------------------------
@@ -53,14 +72,14 @@ func test_session_manager_autoload_exists() -> void:
 # ---------------------------------------------------------------------------
 
 func test_new_game_returns_non_empty_string() -> void:
-	var game_id := SessionManager.new_game()
+	var game_id := _new_game()
 	assert_str(game_id).override_failure_message(
 		"SessionManager.new_game() must return a non-empty game-id string"
 	).is_not_empty()
 
 
 func test_new_game_sets_current_game_id_on_gamestate() -> void:
-	var game_id := SessionManager.new_game()
+	var game_id := _new_game()
 	assert_str(GameState.current_game_id).override_failure_message(
 		"new_game() must set GameState.current_game_id"
 	).is_equal(game_id)
@@ -68,7 +87,7 @@ func test_new_game_sets_current_game_id_on_gamestate() -> void:
 
 func test_new_game_id_format_has_two_dashes() -> void:
 	## Format: <YYYYMMDD>-<HHMMSS>-<hex6> — two separator dashes.
-	var game_id := SessionManager.new_game()
+	var game_id := _new_game()
 	var parts := game_id.split("-")
 	assert_int(parts.size()).override_failure_message(
 		"game-id must have format <YYYYMMDD>-<HHMMSS>-<hex6> (3 parts separated by '-')"
@@ -77,7 +96,7 @@ func test_new_game_id_format_has_two_dashes() -> void:
 
 func test_new_game_id_first_part_is_8_digits() -> void:
 	## First part is YYYYMMDD — 8 decimal digits.
-	var game_id := SessionManager.new_game()
+	var game_id := _new_game()
 	var parts := game_id.split("-")
 	assert_int(parts[0].length()).override_failure_message(
 		"game-id first part (date) must be 8 characters (YYYYMMDD)"
@@ -86,7 +105,7 @@ func test_new_game_id_first_part_is_8_digits() -> void:
 
 func test_new_game_id_second_part_is_6_digits() -> void:
 	## Second part is HHMMSS — 6 decimal digits.
-	var game_id := SessionManager.new_game()
+	var game_id := _new_game()
 	var parts := game_id.split("-")
 	assert_int(parts[1].length()).override_failure_message(
 		"game-id second part (time) must be 6 characters (HHMMSS)"
@@ -95,7 +114,7 @@ func test_new_game_id_second_part_is_6_digits() -> void:
 
 func test_new_game_id_third_part_is_6_hex_chars() -> void:
 	## Third part is 6 hex characters (RNG seed).
-	var game_id := SessionManager.new_game()
+	var game_id := _new_game()
 	var parts := game_id.split("-")
 	assert_int(parts[2].length()).override_failure_message(
 		"game-id third part (hex seed) must be 6 characters"
@@ -105,8 +124,8 @@ func test_new_game_id_third_part_is_6_hex_chars() -> void:
 func test_new_game_ids_are_unique() -> void:
 	## Two rapid new_game() calls should produce different IDs
 	## (different RNG seeds; same-second timestamps are valid but seeds differ).
-	var id1 := SessionManager.new_game()
-	var id2 := SessionManager.new_game()
+	var id1 := _new_game()
+	var id2 := _new_game()
 	# Check that hex seeds differ (they almost certainly will)
 	var seed1 := id1.split("-")[2]
 	var seed2 := id2.split("-")[2]

client/ui/main_menu.gd

@@ -32,7 +32,10 @@ func _refresh_continue_state() -> void:
 
 
 func _on_new_game() -> void:
-	SessionManager.new_game()
+	var game_id := SessionManager.new_game()
+	if game_id.is_empty():
+		push_error("MainMenu: new_game() failed to create save directory — cannot start")
+		return
 	get_tree().change_scene_to_file(GAME_SCENE)