add test_grapheme_clusters.py from pull request #391

Author: astanin

test/test_grapheme_clusters.py

@@ -0,0 +1,239 @@
+"""Tests for Unicode grapheme cluster handling in tabulate."""
+
+import pytest
+
+from tabulate import tabulate
+
+try:
+    import wcwidth
+
+    HAS_WCWIDTH = True
+    HAS_WCWIDTH_030 = hasattr(wcwidth, "wrap")
+except ImportError:
+    wcwidth = None
+    HAS_WCWIDTH = False
+    HAS_WCWIDTH_030 = False
+
+requires_wcwidth = pytest.mark.skipif(not HAS_WCWIDTH, reason="requires wcwidth")
+
+requires_wcwidth_030 = pytest.mark.skipif(not HAS_WCWIDTH_030, reason="requires wcwidth >= 0.3.0")
+
+
+class TestGraphemeClusterWidth:
+    """Tests for correct width calculation of grapheme clusters."""
+
+    @requires_wcwidth
+    def test_zwj_family_emoji_width(self):
+        """ZWJ family emoji has display width 2."""
+        family = "\U0001f468\u200d\U0001f469\u200d\U0001f467"
+        assert wcwidth.wcswidth(family) == 2
+
+    @requires_wcwidth
+    def test_regional_indicator_flag_width(self):
+        """Regional indicator pair (flag) has display width 2."""
+        us_flag = "\U0001f1fa\U0001f1f8"
+        assert wcwidth.wcswidth(us_flag) == 2
+
+    @requires_wcwidth
+    def test_vs16_emoji_width(self):
+        """VS16 variation selector creates wide emoji."""
+        heart = "\u2764\ufe0f"
+        assert wcwidth.wcswidth(heart) == 2
+
+
+class TestGraphemeClusterAlignment:
+    """Tests for correct alignment of cells containing grapheme clusters."""
+
+    @requires_wcwidth
+    def test_zwj_alignment_in_grid(self):
+        """ZWJ emoji aligns correctly in grid format."""
+        family = "\U0001f468\u200d\U0001f469\u200d\U0001f467"
+        data = [
+            ["ABC", "text"],
+            [family, "emoji"],
+        ]
+        result = tabulate(data, headers=["col", "desc"], tablefmt="grid")
+        lines = result.split("\n")
+
+        border_width = len(lines[0])
+        for line in lines:
+            from tabulate import _visible_width
+
+            assert _visible_width(line) == border_width
+
+    @requires_wcwidth
+    def test_flag_alignment_in_grid(self):
+        """Regional indicator flags align correctly in grid format."""
+        us_flag = "\U0001f1fa\U0001f1f8"
+        data = [
+            ["AB", "text"],
+            [us_flag, "flag"],
+        ]
+        result = tabulate(data, headers=["col", "desc"], tablefmt="grid")
+        lines = result.split("\n")
+
+        border_width = len(lines[0])
+        for line in lines:
+            from tabulate import _visible_width
+
+            assert _visible_width(line) == border_width
+
+
+class TestGraphemeClusterWrapping:
+    """Tests for grapheme cluster preservation during text wrapping.
+
+    These tests require wcwidth >= 0.3.0 for iter_graphemes and wrap() APIs.
+    """
+
+    @requires_wcwidth_030
+    def test_zwj_not_broken_during_wrap(self):
+        """ZWJ sequence preserved as single unit during wrap."""
+        family = "\U0001f468\u200d\U0001f469\u200d\U0001f467"
+        data = [[f"A{family}B"]]
+        result = tabulate(data, tablefmt="plain", maxcolwidths=3)
+
+        graphemes_in_result = []
+        for line in result.split("\n"):
+            graphemes_in_result.extend(list(wcwidth.iter_graphemes(line.strip())))
+
+        assert family in graphemes_in_result
+
+    @requires_wcwidth_030
+    def test_flag_not_broken_during_wrap(self):
+        """Regional indicator flag preserved as single unit during wrap."""
+        us_flag = "\U0001f1fa\U0001f1f8"
+        gb_flag = "\U0001f1ec\U0001f1e7"
+        fr_flag = "\U0001f1eb\U0001f1f7"
+        flags = us_flag + gb_flag + fr_flag
+
+        data = [[flags]]
+        result = tabulate(data, tablefmt="plain", maxcolwidths=5)
+
+        graphemes_in_result = []
+        for line in result.split("\n"):
+            graphemes_in_result.extend(list(wcwidth.iter_graphemes(line.strip())))
+
+        assert us_flag in graphemes_in_result
+        assert gb_flag in graphemes_in_result
+        assert fr_flag in graphemes_in_result
+
+    @requires_wcwidth_030
+    def test_vs16_not_broken_during_wrap(self):
+        """VS16 variation selector kept with base character during wrap."""
+        heart = "\u2764\ufe0f"
+        data = [[heart * 3]]
+        result = tabulate(data, tablefmt="plain", maxcolwidths=4)
+
+        graphemes_in_result = []
+        for line in result.split("\n"):
+            graphemes_in_result.extend(list(wcwidth.iter_graphemes(line.strip())))
+
+        heart_count = sum(1 for g in graphemes_in_result if g == heart)
+        assert heart_count == 3
+
+    @requires_wcwidth_030
+    def test_skin_tone_modifier_not_broken(self):
+        """Skin tone modifier preserved with emoji during wrap."""
+        wave_light = "\U0001f44b\U0001f3fb"
+        data = [[f"Hi{wave_light}there"]]
+        result = tabulate(data, tablefmt="plain", maxcolwidths=5)
+
+        graphemes_in_result = []
+        for line in result.split("\n"):
+            graphemes_in_result.extend(list(wcwidth.iter_graphemes(line.strip())))
+
+        assert wave_light in graphemes_in_result
+
+
+class TestComplexGraphemeClusters:
+    """Tests for complex grapheme cluster scenarios.
+
+    These tests require wcwidth >= 0.3.0 for iter_graphemes API.
+    """
+
+    @requires_wcwidth_030
+    def test_multiple_zwj_sequences_in_cell(self):
+        """Multiple ZWJ sequences in single cell handled correctly."""
+        family = "\U0001f468\u200d\U0001f469\u200d\U0001f467"
+        technologist = "\U0001f468\U0001f3fb\u200d\U0001f4bb"
+        data = [[f"{family} and {technologist}"]]
+        result = tabulate(data, tablefmt="plain", maxcolwidths=15)
+
+        graphemes_in_result = []
+        for line in result.split("\n"):
+            graphemes_in_result.extend(list(wcwidth.iter_graphemes(line.strip())))
+
+        assert family in graphemes_in_result
+        assert technologist in graphemes_in_result
+
+    @requires_wcwidth_030
+    def test_flags_with_text_wrap(self):
+        """Flags interspersed with text wrap correctly."""
+        us_flag = "\U0001f1fa\U0001f1f8"
+        data = [[f"Visit {us_flag} USA today!"]]
+        result = tabulate(data, tablefmt="plain", maxcolwidths=10)
+
+        graphemes_in_result = []
+        for line in result.split("\n"):
+            graphemes_in_result.extend(list(wcwidth.iter_graphemes(line.strip())))
+
+        assert us_flag in graphemes_in_result
+
+    @requires_wcwidth_030
+    def test_combining_marks_preserved(self):
+        """Combining diacritical marks stay with base character."""
+        e_acute = "e\u0301"
+        data = [[f"caf{e_acute} au lait"]]
+        result = tabulate(data, tablefmt="plain", maxcolwidths=5)
+
+        graphemes_in_result = []
+        for line in result.split("\n"):
+            graphemes_in_result.extend(list(wcwidth.iter_graphemes(line.strip())))
+
+        assert e_acute in graphemes_in_result
+
+
+class TestAnsiWithGraphemeClusters:
+    """Tests for ANSI escape codes combined with grapheme clusters."""
+
+    @requires_wcwidth
+    def test_ansi_colored_zwj_width(self):
+        """ANSI colored ZWJ emoji has correct width."""
+        family = "\U0001f468\u200d\U0001f469\u200d\U0001f467"
+        colored = f"\x1b[31m{family}\x1b[0m"
+
+        from tabulate import _visible_width
+
+        assert _visible_width(colored) == 2
+
+    @requires_wcwidth
+    def test_ansi_colored_zwj_alignment(self):
+        """ANSI colored ZWJ emoji aligns correctly."""
+        family = "\U0001f468\u200d\U0001f469\u200d\U0001f467"
+        colored = f"\x1b[31m{family}\x1b[0m"
+        data = [
+            ["AB", "text"],
+            [colored, "emoji"],
+        ]
+        result = tabulate(data, headers=["col", "desc"], tablefmt="grid")
+        lines = result.split("\n")
+
+        from tabulate import _visible_width
+
+        border_width = _visible_width(lines[0])
+        for line in lines:
+            assert _visible_width(line) == border_width
+
+    @requires_wcwidth_030
+    def test_ansi_colored_flag_wrap(self):
+        """ANSI colored flag not broken during wrap."""
+        us_flag = "\U0001f1fa\U0001f1f8"
+        colored = f"\x1b[34m{us_flag}\x1b[0m"
+        data = [[f"A{colored}B"]]
+        result = tabulate(data, tablefmt="plain", maxcolwidths=4)
+
+        assert "\U0001f1fa" in result
+        assert "\U0001f1f8" in result
+        lines = [line.strip() for line in result.split("\n") if line.strip()]
+        flag_parts_same_line = any("\U0001f1fa" in line and "\U0001f1f8" in line for line in lines)
+        assert flag_parts_same_line