c32swidth: Add tests.

* tests/test-c32swidth.c: New file, based on tests/test-c32width.c.
* modules/c32swidth-tests: New file.

1 files changed, 128 insertions, 0 deletions

diff --git a/tests/test-c32swidth.c b/tests/test-c32swidth.c
new file mode 100644
index 0000000000..8bf19afec9
--- /dev/null
+++ b/tests/test-c32swidth.c
@@ -0,0 +1,128 @@
+/* Test of c32swidth() function.
+   Copyright (C) 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>, 2023.  */
+
+#include <config.h>
+
+#include <uchar.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (c32swidth, int, (const char32_t *, size_t));
+
+#include <locale.h>
+#include <string.h>
+
+#include "localcharset.h"
+#include "macros.h"
+
+int
+main ()
+{
+  int w;
+
+  /* Switch to an UTF-8 locale.  */
+  if (!((setlocale (LC_ALL, "fr_FR.UTF-8") != NULL
+         || setlocale (LC_ALL, "de_DE.UTF-8") != NULL
+         || setlocale (LC_ALL, "es_ES.UTF-8") != NULL
+         || setlocale (LC_ALL, "en_US.UTF-8") != NULL)
+        /* Check whether it's really an UTF-8 locale.
+           On native Windows, these setlocale calls succeed but the encoding
+           of this locale is CP1252, not UTF-8.  */
+        && strcmp (locale_charset (), "UTF-8") == 0))
+    {
+      fprintf (stderr, "Skipping test: No common Unicode locale is installed\n");
+      return 77;
+    }
+
+  {
+    char32_t s[] = { 'f', 'p', 0, 'x' };
+    w = c32swidth (s, 0);
+    ASSERT (w == 0);
+    w = c32swidth (s, 1);
+    ASSERT (w == 1);
+    w = c32swidth (s, 2);
+    ASSERT (w == 2);
+    w = c32swidth (s, 3);
+    ASSERT (w == 2);
+    w = c32swidth (s, 4);
+    ASSERT (w == 2);
+    w = c32swidth (s, (size_t)(-1));
+    ASSERT (w == 2);
+  }
+
+  {
+    char32_t s[] = { 'f', 'p', '\n', 'x' };
+    w = c32swidth (s, 0);
+    ASSERT (w == 0);
+    w = c32swidth (s, 1);
+    ASSERT (w == 1);
+    w = c32swidth (s, 2);
+    ASSERT (w == 2);
+    w = c32swidth (s, 3);
+    ASSERT (w == -1);
+    w = c32swidth (s, 4);
+    ASSERT (w == -1);
+  }
+
+  /* Test width of some non-spacing characters.  */
+  {
+    char32_t s[] = { 'a', 0x0301 };
+    w = c32swidth (s, 2);
+    ASSERT (w == 1);
+  }
+
+  /* Test width of some zero width characters.  */
+  {
+    char32_t s[] = { 'i', 0x200B, 'j' };
+    w = c32swidth (s, 3);
+    ASSERT (w == 2);
+  }
+
+  /* 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.
+     The chosen locale above is a Western locale, not an East Asian locale,
+     therefore U+2202 should be treated like a narrow character.  */
+  {
+    char32_t s[] = { 0x2202 };
+    w = c32swidth (s, 1);
+    ASSERT (w == 1);
+  }
+
+  /* Test width of some CJK characters.  */
+  {
+    char32_t s[] = { 0x4E2D, 0x6587 };
+    w = c32swidth (s, 2);
+    ASSERT (w == 4);
+  }
+  {
+    char32_t s[] = { 0x20369, 0x2F876 };
+    w = c32swidth (s, 2);
+    ASSERT (w == 4);
+  }
+
+  return 0;
+}