Add tests for mu_str_expand and mu_str_vexpand functions

* libmailutils/string/expvar.c (exp_shell): Fix out-of-buffer
read when used without arguments.
(mu_str_expand): Improve error handling.
* libmailutils/tests/testsuite.at (MU_GENERIC_TEST_CMD): New
macro.
Include exp.at
* libmailutils/tests/vexp.c: New file.
* libmailutils/tests/Makefile.am: Build vexp. Add exp.at
* libmailutils/tests/exp.at: New file.

@@ -229,8 +229,8 @@ exp_runcmd (char **ret, const char *str, size_t len, char **argv, void *closure)
 
   if (strcmp (argv[0], SHELL_CMD) == 0)
     {
-      len -= sizeof SHELL_CMD;
-      str += sizeof SHELL_CMD;
+      len -= sizeof SHELL_CMD - 1;
+      str += sizeof SHELL_CMD - 1;
       while (len > 0 && mu_isspace (*str))
 	{
 	  len--;
@@ -282,8 +282,7 @@ int
 mu_str_expand (char **output, char const *input, mu_assoc_t assoc)
 {
   struct mu_wordsplit ws;
-  size_t wordc;
-  char **wordv;
+  int rc = 0;
   
   ws.ws_getvar = exp_getvar;
   ws.ws_command = exp_runcmd;
@@ -294,15 +293,36 @@ mu_str_expand (char **output, char const *input, mu_assoc_t assoc)
 		    MU_WRDSF_NOSPLIT | MU_WRDSF_GETVAR | MU_WRDSF_CLOSURE
 		    | MU_WRDSF_OPTIONS))
     {
+      if (ws.ws_errno == MU_WRDSE_NOSPACE)
+	rc = ENOMEM;
+      else
+	{
 	  char *p = strdup (mu_wordsplit_strerror (&ws));
-      if (p)
+	  if (!p)
+	    rc = ENOMEM;
+	  else
+	    {
 	      *output = p;
-      return MU_ERR_FAILURE;
+	      rc = MU_ERR_FAILURE;
+	    }
 	}
+    }
+  else if (ws.ws_wordc == 0)
+    {
+      *output = strdup ("");
+      if (!*output)
+	rc = ENOMEM;
+    }
+  else
+    {
+      size_t wordc;
+      char **wordv;
+      
       mu_wordsplit_get_words (&ws, &wordc, &wordv);
       *output = wordv[0];
+    }
   mu_wordsplit_free (&ws);
-  return 0;
+  return rc;
 }
 
 int

@@ -11,6 +11,7 @@ argcv
 debugspec
 decode2047
 encode2047
+exp
 fltst
 fsaf
 fsaftomod
@@ -34,6 +35,7 @@ tcli
 tempfile
 url-comp
 url-parse
+vexp
 wicket
 wordwrap
 wsp

@@ -70,6 +70,7 @@ noinst_PROGRAMS = \
  tcli\
  url-comp\
  url-parse\
+ vexp\
  wicket\
  wordwrap\
  wsp
@@ -89,6 +90,7 @@ TESTSUITE_AT = \
  debugspec.at\
  decode2047.at\
  encode2047.at\
+ exp.at\
  fromflt.at\
  fsaf.at\
  fsaftomod.at\

+# This file is part of GNU Mailutils. -*- Autotest -*-
+# Copyright (C) 2007-2012, 2014-2017 Free Software Foundation, Inc.
+#
+# GNU Mailutils 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, or (at
+# your option) any later version.
+#
+# GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>.
+
+AT_BANNER(Variable and command expansion)
+
+dnl ------------------------------------------------------------
+dnl TESTEXP([NAME], [KW = `'], [INPUT], [STDOUT = `'],
+dnl         [STDERR = `'])
+dnl
+m4_pushdef([TESTEXP],[
+m4_pushdef([MU_TEST_GROUP],[Expand])
+m4_pushdef([MU_TEST_KEYWORDS],[expand])
+MU_GENERIC_TEST_CMD([$1],[$2],[$3],[],[$4
+],[$5])
+m4_popdef([MU_TEST_KEYWORDS])
+m4_popdef([MU_TEST_GROUP])
+])
+
+m4_pushdef([MU_TEST_COMMAND],[exp])
+TESTEXP([variable expansion],[],[x=foo y=bar -- 'test $x $y $z end'],
+[test foo bar  end])
+
+TESTEXP([domainpart],[],[-- '$(domainpart "foo@example.com")'],
+[example.com])
+
+TESTEXP([localpart],[],[-- '$(localpart "foo@example.com")'],
+[foo])
+
+TESTEXP([shell],[],[-- '$(shell echo "test string" | tr " " -)'],
+[test-string])
+
+m4_popdef([MU_TEST_COMMAND])
+
+m4_pushdef([MU_TEST_COMMAND],[vexp])
+TESTEXP([mu_str_vexpand],[],['certain $user on $host running $package'],
+[certain somebody on localhost running mailutils])
+
+m4_popdef([MU_TEST_COMMAND])
+m4_popdef([TESTEXP])
\ No newline at end of file

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2017 Free Software Foundation, Inc.
+
+   GNU Mailutils 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, or (at your option)
+   any later version.
+
+   GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>. */
+
 #include <mailutils/mailutils.h>
 
 int

@@ -51,6 +51,28 @@ MU_TEST_COMMAND < input],[$4],[$5],[$6],[$7],[$8])
 AT_CLEANUP
 ])
 
+dnl ------------------------------------------------------------
+dnl MU_GENERIC_TEST_CMD([NAME], [KW = `'], [ARGS],
+dnl                     [CODE], [STDOUT = `'], [STDERR = `'],
+dnl                     [RUN-IF-FAIL], [RUN-IF-PASS])
+dnl
+dnl NAME        $1
+dnl KW          $2
+dnl ARGS        $3
+dnl CODE        $4
+dnl STDOUT      $5
+dnl STDERR      $6
+dnl RUN-IF-FAIL $7
+dnl RUN-IF-PASS $8
+dnl
+m4_define([MU_GENERIC_TEST_CMD],[
+AT_SETUP([m4_if(MU_TEST_GROUP,[],,MU_TEST_GROUP: )m4_if([$1],[],[mu_firstline([$3])],[$1])])
+AT_KEYWORDS([MU_TEST_KEYWORDS $2])
+AT_CHECK([
+MU_TEST_COMMAND $3],[$4],[$5],[$6],[$7],[$8])
+AT_CLEANUP
+])
+
 AT_INIT
 
 AT_BANNER([Conversions])
@@ -131,6 +153,7 @@ m4_include([strerr.at])
 m4_include([list.at])
 m4_include([address.at])
 m4_include([wordsplit.at])
+m4_include([exp.at])
 m4_include([url.at])
 m4_include([url-comp.at])
 m4_include([mailcap.at])

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2017 Free Software Foundation, Inc.
+
+   GNU Mailutils 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, or (at your option)
+   any later version.
+
+   GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include <mailutils/mailutils.h>
+#include <assert.h>
+
+int
+main (int argc, char **argv)
+{
+  int rc;
+  char *p;
+
+  assert (argc == 2);
+
+  rc = mu_str_vexpand (&p, argv[1],
+		       "user", "somebody",
+		       "host", "localhost",
+		       "name", "tests",
+		       "package", PACKAGE,
+		       NULL);
+  switch (rc)
+    {
+    case 0:
+      printf ("%s\n", p);
+      free (p);
+      break;
+      
+    case MU_ERR_FAILURE:
+      mu_error ("%s", p);
+      free (p);
+      break;
+      
+    default:
+      mu_error ("%s", mu_strerror (rc));
+      return 1;
+    }
+  return 0;
+}