c32width: Add tests.

* tests/test-c32width.c: New file, based on tests/test-wcwidth.c.
* modules/c32width-tests: New file.

3 files changed, 122 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 9bfa9e0c48..fcb9afb7d5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2023-05-04  Bruno Haible  <bruno@clisp.org>
 
+	c32width: Add tests.
+	* tests/test-c32width.c: New file, based on tests/test-wcwidth.c.
+	* modules/c32width-tests: New file.
+
 	c32width: New module.
 	* lib/uchar.in.h (c32width): New declaration.
 	* lib/c32width.c: New file, based on lib/c32is-impl.h.
diff --git a/modules/c32width-tests b/modules/c32width-tests
new file mode 100644
index 0000000000..caa18b362d
--- /dev/null
+++ b/modules/c32width-tests
@@ -0,0 +1,16 @@
+Files:
+tests/test-c32width.c
+tests/signature.h
+tests/macros.h
+
+Depends-on:
+c-ctype
+localcharset
+setlocale
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-c32width
+check_PROGRAMS += test-c32width
+test_c32width_LDADD = $(LDADD) $(SETLOCALE_LIB) $(LIBUNISTRING)
diff --git a/tests/test-c32width.c b/tests/test-c32width.c
new file mode 100644
index 0000000000..24966f963e
--- /dev/null
+++ b/tests/test-c32width.c
@@ -0,0 +1,102 @@
+/* Test of c32width() function.
+   Copyright (C) 2007-2023 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2007.  */
+
+#include <config.h>
+
+#include <uchar.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (c32width, int, (char32_t));
+
+#include <locale.h>
+#include <string.h>
+
+#include "c-ctype.h"
+#include "localcharset.h"
+#include "macros.h"
+
+int
+main ()
+{
+  char32_t wc;
+
+#if !GNULIB_WCHAR_SINGLE_LOCALE
+# ifdef C_CTYPE_ASCII
+  /* Test width of ASCII characters.  */
+  for (wc = 0x20; wc < 0x7F; wc++)
+    ASSERT (c32width (wc) == 1);
+# endif
+#endif
+
+  /* Switch to an UTF-8 locale.  */
+  if (setlocale (LC_ALL, "fr_FR.UTF-8") != NULL
+      /* Check whether it's really an UTF-8 locale.
+         On OpenBSD 4.0, the setlocale call succeeds only for the LC_CTYPE
+         category and therefore returns "C/fr_FR.UTF-8/C/C/C/C", but the
+         LC_CTYPE category is effectively set to an ASCII LC_CTYPE category;
+         in particular, locale_charset() returns "ASCII".  */
+      && strcmp (locale_charset (), "UTF-8") == 0)
+    {
+      /* Test width of ASCII characters.  */
+      for (wc = 0x20; wc < 0x7F; wc++)
+        ASSERT (c32width (wc) == 1);
+
+      /* Test width of some non-spacing characters.  */
+      ASSERT (c32width (0x0301) == 0);
+      ASSERT (c32width (0x05B0) == 0);
+
+      /* Test width of some format control characters.  */
+      ASSERT (c32width (0x200E) <= 0);
+      ASSERT (c32width (0x2060) <= 0);
+      ASSERT (c32width (0xE0001) <= 0);
+      ASSERT (c32width (0xE0044) <= 0);
+
+      /* Test width of some zero width characters.  */
+      /* While it is desirable that U+200B, U+200C, U+200D have width 0,
+         because this makes wcswidth work better on strings that contain these
+         characters, it is acceptable if an implementation treats these
+         characters like control characters.  */
+      ASSERT (c32width (0x200B) <= 0);
+      ASSERT (c32width (0xFEFF) <= 0);
+
+      /* Test width of some math symbols.
+         U+2202 is marked as having ambiguous width (A) in EastAsianWidth.txt
+         (see <https://www.unicode.org/Public/12.0.0/ucd/EastAsianWidth.txt>).
+         The Unicode Standard Annex 11
+         <https://www.unicode.org/reports/tr11/tr11-36.html>
+         says
+           "Ambiguous characters behave like wide or narrow characters
+            depending on the context (language tag, script identification,
+            associated font, source of data, or explicit markup; all can
+            provide the context). If the context cannot be established
+            reliably, they should be treated as narrow characters by default."
+         For c32width(), the only available context information is the locale.
+         "fr_FR.UTF-8" is a Western locale, not an East Asian locale, therefore
+         U+2202 should be treated like a narrow character.  */
+      ASSERT (c32width (0x2202) == 1);
+
+      /* Test width of some CJK characters.  */
+      ASSERT (c32width (0x3000) == 2);
+      ASSERT (c32width (0xB250) == 2);
+      ASSERT (c32width (0xFF1A) == 2);
+      ASSERT (c32width (0x20369) == 2);
+      ASSERT (c32width (0x2F876) == 2);
+    }
+
+  return 0;
+}