tests: exercise a rarely-used corner of copy.c

* tests/cp/sparse-to-pipe: New test.
* tests/Makefile.am (TESTS): Add it.

tests/Makefile.am

@@ -343,6 +343,7 @@ TESTS =						\
   cp/same-file					\
   cp/slink-2-slink				\
   cp/sparse					\
+  cp/sparse-to-pipe				\
   cp/special-f					\
   cp/src-base-dot				\
   cp/symlink-slash				\

tests/cp/sparse-to-pipe

@@ -0,0 +1,31 @@
+#!/bin/sh
+# copy a sparse file to a pipe, to exercise some seldom-used parts of copy.c
+
+# Copyright (C) 2011 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 <http://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/init.sh"; path_prepend_ ../src
+print_ver_ cp
+
+require_sparse_support_
+
+mkfifo_or_skip_ pipe
+timeout 10 cat pipe > copy &
+
+truncate -s1M sparse || framework_failure_
+cp sparse pipe || fail=1
+cmp sparse copy || fail=1
+
+Exit $fail