--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2011-12-22  Jim Meyering  <meyering@redhat.com>
 
+	test-framework-sh: add minimal tests of init.sh's compare function
+	* modules/test-framework-sh-tests: New file.
+	* tests/test-init.sh: New file.
+
 	test-framework-sh: new module
 	* modules/test-framework-sh: New file.
 	* MODULES.html.sh (Support for maintaining and releasing projects):

new file mode 100644
--- /dev/null
+++ b/modules/test-framework-sh-tests
@@ -0,0 +1,9 @@
+Files:
+tests/test-init.sh
+
+Depends-on:
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-init.sh

new file mode 100755
--- /dev/null
+++ b/tests/test-init.sh
@@ -0,0 +1,68 @@
+#!/bin/sh
+# Unit tests for init.sh
+# Copyright (C) 2011 Free Software Foundation, Inc.
+# This file is part of the GNUlib Library.
+#
+# 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 <http://www.gnu.org/licenses/>.  */
+
+: ${srcdir=.}
+. "$srcdir/init.sh"; path_prepend_ .
+
+fail=0
+
+test_compare()
+{
+  touch empty || fail=1
+  echo xyz > in || fail=1
+
+  compare /dev/null /dev/null >out 2>err || fail=1
+  test -s out && fail_ "out not empty: $(cat out)"
+  # "err" should be empty, too, but has "set -x" output when VERBOSE=yes
+  case $- in *x*) ;; *) test -s err && fail_ "err not empty: $(cat err)";; esac
+
+  compare /dev/null empty >out 2>err || fail=1
+  test -s out && fail_ "out not empty: $(cat out)"
+  case $- in *x*) ;; *) test -s err && fail_ "err not empty: $(cat err)";; esac
+
+  compare in in >out 2>err || fail=1
+  test -s out && fail_ "out not empty: $(cat out)"
+  case $- in *x*) ;; *) test -s err && fail_ "err not empty: $(cat err)";; esac
+
+  compare /dev/null in >out 2>err && fail=1
+  cat <<\EOF > exp
+diff -u /dev/null in
+--- /dev/null	1970-01-01
++++ in	1970-01-01
++xyz
+EOF
+  compare exp out || fail=1
+  case $- in *x*) ;; *) test -s err && fail_ "err not empty: $(cat err)";; esac
+
+  compare empty in >out 2>err && fail=1
+  # Remove the TAB-date suffix on each --- and +++ line,
+  # for both the expected and the actual output files.
+  cat <<\EOF > exp
+--- empty
++++ in
+@@ -0,0 +1 @@
++xyz
+EOF
+  sed 's/	.*//' out > k && mv k out
+  compare exp out || fail=1
+  case $- in *x*) ;; *) test -s err && fail_ "err not empty: $(cat err)";; esac
+}
+
+test_compare
+
+Exit $fail