tests: correct racy sparse-to-pipe test

* tests/cp/sparse-to-pipe: Wait for backgrounded "cat" to complete
before comparing the results.

diff --git a/tests/cp/sparse-to-pipe b/tests/cp/sparse-to-pipe
index 4d39458..9bbaafa 100755 (executable)
--- a/tests/cp/sparse-to-pipe
+++ b/tests/cp/sparse-to-pipe
@@ -26,6 +26,10 @@ timeout 10 cat pipe > copy &
 
 truncate -s1M sparse || framework_failure_
 cp sparse pipe || fail=1
+
+# Ensure that the cat has completed before comparing.
+wait
+
 cmp sparse copy || fail=1
 
 Exit $fail