mbstoc32s tests: Check behaviour in the C locale.

* tests/test-mbstoc32s.c (main): Test behaviour in the C locale. Based
on tests/test-mbstowcs.c.
* tests/test-mbstoc32s-5.sh: New file, based on tests/test-mbstowcs5.sh.
* modules/mbstoc32s-tests (Files): Add it.
(Depends-on): Add btoc32.
(Makefile.am): Run test-mbstoc32s-5.sh.

2 files changed, 75 insertions, 0 deletions

diff --git a/tests/test-mbstoc32s-5.sh b/tests/test-mbstoc32s-5.sh
new file mode 100755
index 0000000000..edb36432b8
--- /dev/null
+++ b/tests/test-mbstoc32s-5.sh
@@ -0,0 +1,9 @@
+#!/bin/sh
+
+# Test whether the POSIX locale has encoding errors.
+LC_ALL=C \
+${CHECKER} ./test-mbstoc32s${EXEEXT} 5 || exit 1
+LC_ALL=POSIX \
+${CHECKER} ./test-mbstoc32s${EXEEXT} 5 || exit 1
+
+exit 0
diff --git a/tests/test-mbstoc32s.c b/tests/test-mbstoc32s.c
index 5358118906..e638999bb6 100644
--- a/tests/test-mbstoc32s.c
+++ b/tests/test-mbstoc32s.c
@@ -64,6 +64,15 @@ main (int argc, char *argv[])
     ASSERT (wc == 0);
   }
 
+#ifdef __ANDROID__
+  /* On Android ≥ 5.0, the default locale is the "C.UTF-8" locale, not the
+     "C" locale.  Furthermore, when you attempt to set the "C" or "POSIX"
+     locale via setlocale(), what you get is a "C" locale with UTF-8 encoding,
+     that is, effectively the "C.UTF-8" locale.  */
+  if (argc > 1 && strcmp (argv[1], "5") == 0 && MB_CUR_MAX > 1)
+    argv[1] = "2";
+#endif
+
   if (argc > 1)
     {
       int unlimited;
@@ -232,6 +241,63 @@ main (int argc, char *argv[])
               }
               break;
 
+            case '5':
+              /* C or POSIX locale.  */
+              {
+                char input[] = "n/a";
+
+                src = input;
+                ret = mbstoc32s (NULL, src, unlimited ? BUFSIZE : 1);
+                ASSERT (ret == 3);
+
+                src = input;
+                ret = mbstoc32s (buf, src, unlimited ? BUFSIZE : 1);
+                ASSERT (ret == (unlimited ? 3 : 1));
+                ASSERT (buf[0] == 'n');
+                if (unlimited)
+                  {
+                    ASSERT (buf[1] == '/');
+                    ASSERT (buf[2] == 'a');
+                    ASSERT (buf[3] == 0);
+                    ASSERT (buf[4] == (char32_t) 0xBADFACE);
+                  }
+                else
+                  ASSERT (buf[1] == (char32_t) 0xBADFACE);
+              }
+              {
+                int c;
+                char input[2];
+
+                for (c = 0; c < 0x100; c++)
+                  if (c != 0)
+                    {
+                      /* We are testing all nonnull bytes.  */
+                      input[0] = c;
+                      input[1] = '\0';
+
+                      src = input;
+                      ret = mbstoc32s (NULL, src, unlimited ? BUFSIZE : 1);
+                      ASSERT (ret == 1);
+
+                      buf[0] = buf[1] = (char32_t) 0xBADFACE;
+                      src = input;
+                      ret = mbstoc32s (buf, src, unlimited ? BUFSIZE : 1);
+                      /* POSIX:2018 says regarding mbstowcs: "In the POSIX locale an
+                         [EILSEQ] error cannot occur since all byte values are valid
+                         characters."  It is reasonable to expect mbstoc32s to behave
+                         in the same way.  */
+                      ASSERT (ret == 1);
+                      if (c < 0x80)
+                        /* c is an ASCII character.  */
+                        ASSERT (buf[0] == c);
+                      else
+                        /* On most platforms, the bytes 0x80..0xFF map to U+0080..U+00FF.
+                           But on musl libc, the bytes 0x80..0xFF map to U+DF80..U+DFFF.  */
+                        ASSERT (buf[0] == (btoc32 (c) == 0xDF00 + c ? btoc32 (c) : c));
+                    }
+              }
+              break;
+
             default:
               return 1;
             }