Merge pull request #4007 from Textualize/copilot/sub-pr-4006

Add regression tests for VS16 after zero-width chars in split_graphemes

Author: willmcgugan

tests/test_cells.py

@@ -209,6 +209,16 @@ def test_is_single_cell_widths() -> None:
             [(0, 2, 0)],
             0,
         ),  # Two ZWJs should have zero width
+        (
+            "\x1b\ufe0f",
+            [(0, 2, 0)],
+            0,
+        ),  # VS16 after escape (zero-width, doesn't set last_measured_character) should have zero width
+        (
+            "\u200d\ufe0f",
+            [(0, 2, 0)],
+            0,
+        ),  # VS16 after ZWJ (zero-width, doesn't set last_measured_character) should have zero width
     ],
 )
 def test_split_graphemes(