tests: fail rather than infloop in tail's inotify-rotate test

* tests/tail-2/inotify-rotate: Switch to new init.sh-based framework.
(grep_timeout): New function.
Use it in place of open-coded loops that might infloop.
This was prompted by my encountering an inexplicable, and so far
unreproducible, infloop in the code that was waiting for "b" to
appear in "out".

1 files changed, 16 insertions, 6 deletions

diff --git a/tests/tail-2/inotify-rotate b/tests/tail-2/inotify-rotate
index 51cd81bb1..9a3933e83 100755
--- a/tests/tail-2/inotify-rotate
+++ b/tests/tail-2/inotify-rotate
@@ -21,9 +21,21 @@ if test "$VERBOSE" = yes; then
   tail --version
 fi
 
-. $srcdir/test-lib.sh
+. "${srcdir=.}/init.sh"; path_prepend_ ../src
 expensive_
 
+# Wait up to 10 seconds for grep REGEXP FILE to succeed.
+# Usage: grep_timeout REGEXP FILE
+grep_timeout()
+{
+    local j
+    for j in $(seq 100); do
+        grep $1 $2 > /dev/null && return 0
+        sleep 0.1
+    done
+    return 1
+}
+
 # For details, see
 # http://lists.gnu.org/archive/html/bug-coreutils/2009-11/msg00213.html
 
@@ -37,17 +49,15 @@ for i in $(seq 50); do
     sleep .1
     echo b > k;
     # wait for b to appear in out
+    grep_timeout b out || fail_ failed to find b in out
     while :; do grep b out > /dev/null && break; done
     mv x k
     # wait for tail to detect the rename
-    while :; do grep tail: out > /dev/null && break; done
+    grep_timeout tail: out || fail_ failed to detect rename
     echo ok >> k
     found=0
     # wait up to 10 seconds for "ok" to appear in out
-    for j in $(seq 100); do
-        grep ok out > /dev/null && { found=1; break; }
-        sleep 0.1
-    done
+    grep_timeout ok out && found=1
     kill $pid
     test $found = 0 && { fail=1; cat out; break; }
 done