Add test for warn, warnx, vwarn, and vwarnx with floating-point parameters

Similarly to what has been done for argp_error and argp_failure, this
patch patch adds new tests for the warn, warnx, vwarn, and vwarnx
functions.  The new tests use the format string to request the
conversion of long double parameters into string.  Currently, these
tests only check that the default format of the long double type works.
Future patches will extend the test for platforms that can have an
optional format for long double.

Tested for powerpc64le.

	* misc/Makefile (tests): Add tst-ldbl-warn.
	* misc/tst-ldbl-warn.c: New file.

2 files changed, 122 insertions, 1 deletions

diff --git a/misc/Makefile b/misc/Makefile
index 30e0673c8a..201de124f4 100644
--- a/misc/Makefile
+++ b/misc/Makefile
@@ -84,7 +84,8 @@ tests := tst-dirname tst-tsearch tst-fdset tst-efgcvt tst-mntent tst-hsearch \
 	 tst-error1 tst-pselect tst-insremque tst-mntent2 bug-hsearch1 \
 	 tst-mntent-blank-corrupt tst-mntent-blank-passno bug18240 \
 	 tst-preadvwritev tst-preadvwritev64 tst-makedev tst-empty \
-	 tst-preadvwritev2 tst-preadvwritev64v2 tst-warn-wide
+	 tst-preadvwritev2 tst-preadvwritev64v2 tst-warn-wide \
+	 tst-ldbl-warn
 
 # Tests which need libdl.
 ifeq (yes,$(build-shared))
diff --git a/misc/tst-ldbl-warn.c b/misc/tst-ldbl-warn.c
new file mode 100644
index 0000000000..3ac0e4c873
--- /dev/null
+++ b/misc/tst-ldbl-warn.c
@@ -0,0 +1,120 @@
+/* Test for the long double conversions in *warn* functions.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <err.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <support/check.h>
+#include <support/xmemstream.h>
+
+enum {WARN, WARNX, VWARN, VWARNX};
+
+static void
+do_one_test (int select, const char *format, va_list args,
+	     long double arg1, double arg2, long double arg3,
+	     double arg4, const char *expected)
+{
+  /* Prepare in-memory buffer to hold the output.  */
+  struct xmemstream stream;
+  xopen_memstream (&stream);
+  FILE *old_stderr = stderr;
+  stderr = stream.out;
+
+  /* Write to the buffer using one of the *warn* functions.  */
+  errno = 0;
+  switch (select)
+    {
+      case WARN:
+	warn (format, arg1, arg2, arg3, arg4);
+	break;
+      case WARNX:
+	warnx (format, arg1, arg2, arg3, arg4);
+	break;
+      case VWARN:
+	vwarn (format, args);
+	break;
+      case VWARNX:
+	vwarnx (format, args);
+	break;
+    }
+
+  stderr = old_stderr;
+
+  /* Close the in-memory stream and check the output buffer.  */
+  xfclose_memstream (&stream);
+  if (strcmp (stream.buffer, expected) != 0)
+    FAIL_EXIT1 ("error:\n"
+		"    expected: '%s'\n"
+		"      actual: '%s'\n",
+		expected, stream.buffer);
+
+  if (stream.buffer != NULL)
+    free (stream.buffer);
+}
+
+static void
+do_test_call_varg (const char *format, ...)
+{
+  va_list args;
+
+  va_start (args, format);
+  do_one_test (VWARN, format, args, 0, 0, 0, 0,
+	       "tst-ldbl-warn: "
+	       "-1.000000 - -2.000000 - -3.000000 - -4.000000: Success\n");
+  va_end (args);
+
+  va_start (args, format);
+  do_one_test (VWARNX, format, args, 0, 0, 0, 0,
+	       "tst-ldbl-warn: "
+	       "-1.000000 - -2.000000 - -3.000000 - -4.000000\n");
+  va_end (args);
+}
+
+static void
+do_test_call_rarg (const char *format, long double arg1, double arg2,
+		   long double arg3, double arg4)
+{
+  va_list args;
+  memset (&args, 0, sizeof (args));
+  do_one_test (WARN, format, args, arg1, arg2, arg3, arg4,
+	       "tst-ldbl-warn: "
+	       "-1.000000 - -2.000000 - -3.000000 - -4.000000: Success\n");
+  do_one_test (WARNX, format, args, arg1, arg2, arg3, arg4,
+	       "tst-ldbl-warn: "
+	       "-1.000000 - -2.000000 - -3.000000 - -4.000000\n");
+}
+
+static int
+do_test (void)
+{
+  long double arg1 = -1;
+  long double arg3 = -3;
+  double arg2 = -2;
+  double arg4 = -4;
+
+  do_test_call_rarg ("%Lf - %f - %Lf - %f", arg1, arg2, arg3, arg4);
+  do_test_call_varg ("%Lf - %f - %Lf - %f", arg1, arg2, arg3, arg4);
+
+  return 0;
+}
+
+#include <support/test-driver.c>