tests: implemented tile_offset test

tests/test_data/tilesets/image_tile_offset/expected.py

@@ -0,0 +1,20 @@
+from pathlib import Path
+
+from pytiled_parser import tileset
+from pytiled_parser.common_types import Color, OrderedPair
+
+EXPECTED = tileset.TileSet(
+    columns=8,
+    image=Path("../../maps/images/tmw_desert_spacing.png"),
+    image_height=199,
+    image_width=265,
+    margin=1,
+    spacing=1,
+    name="tile_set_image",
+    tile_count=48,
+    tiled_version="1.3.5",
+    tile_height=32,
+    tile_width=32,
+    version=1.2,
+    tile_offset=OrderedPair(3, 5),
+)