test(lua.endpoints): add screenshot endpoint tests

Author: S1M0N38

tests/lua/endpoints/test_screenshot.py

@@ -0,0 +1,66 @@
+"""Tests for src/lua/endpoints/screenshot.lua"""
+
+import socket
+from pathlib import Path
+
+import pytest
+
+from tests.lua.conftest import (
+    api,
+    assert_error_response,
+    assert_gamestate_response,
+    assert_path_response,
+    load_fixture,
+)
+
+
+class TestScreenshotEndpoint:
+    """Test basic screenshot endpoint functionality."""
+
+    def test_screenshot_from_MENU(self, client: socket.socket, tmp_path: Path) -> None:
+        """Test that screenshot succeeds from MENU state."""
+        gamestate = api(client, "menu", {})
+        assert_gamestate_response(gamestate, state="MENU")
+        temp_file = tmp_path / "screenshot.png"
+        response = api(client, "screenshot", {"path": str(temp_file)})
+        assert_path_response(response)
+        assert response["result"]["path"] == str(temp_file)
+        assert temp_file.exists()
+        assert temp_file.stat().st_size > 0
+        assert temp_file.read_bytes()[:8] == b"\x89PNG\r\n\x1a\n"
+
+    def test_screenshot_from_BLIND_SELECT(
+        self, client: socket.socket, tmp_path: Path
+    ) -> None:
+        """Test that screenshot succeeds from BLIND_SELECT state."""
+        gamestate = load_fixture(client, "screenshot", "state-BLIND_SELECT")
+        assert gamestate["state"] == "BLIND_SELECT"
+        temp_file = tmp_path / "screenshot.png"
+        response = api(client, "screenshot", {"path": str(temp_file)})
+        assert_path_response(response)
+        assert response["result"]["path"] == str(temp_file)
+        assert temp_file.exists()
+        assert temp_file.stat().st_size > 0
+        assert temp_file.read_bytes()[:8] == b"\x89PNG\r\n\x1a\n"
+
+
+class TestScreenshotValidation:
+    """Test screenshot endpoint parameter validation."""
+
+    def test_missing_path_parameter(self, client: socket.socket) -> None:
+        """Test that screenshot fails when path parameter is missing."""
+        response = api(client, "screenshot", {})
+        assert_error_response(
+            response,
+            "BAD_REQUEST",
+            "Missing required field 'path'",
+        )
+
+    def test_invalid_path_type(self, client: socket.socket) -> None:
+        """Test that screenshot fails when path is not a string."""
+        response = api(client, "save", {"path": 123})
+        assert_error_response(
+            response,
+            "BAD_REQUEST",
+            "Field 'path' must be of type string",
+        )