tests: use trap mechanism to ensure that proper cleanups happen

This actually consists of several parts.

  * Added a generic cleanup-scheduling mechanism.  Instead of calling
    "trap ... EXIT" directly, just call "push_trapfunc ..." instead and
    your cleanup function will be called along with any others.

  * Converted a few tests to use push_trapfunc.

  * Added "push_trapfunc cleanup_lvm" to snapshot.rc to address the
    particular problem that's driving this - snapshot tests not calling
    cleanup_lvm on their own and leaving bad state for the next test.

Change-Id: I548a97a26328390992fc71ee1f03c0463703f9d7
Signed-off-by: Jeff Darcy <jdarcy@redhat.com>
Reviewed-on: http://review.gluster.org/13933
Smoke: Gluster Build System <jenkins@build.gluster.com>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Atin Mukherjee <amukherj@redhat.com>
Reviewed-by: Rajesh Joseph <rjoseph@redhat.com>

1 files changed, 22 insertions, 0 deletions

diff --git a/tests/traps.rc b/tests/traps.rc
new file mode 100644
index 00000000000..f011960c97e
--- /dev/null
+++ b/tests/traps.rc
@@ -0,0 +1,22 @@
+#!/bin/bash
+
+# Make sure this only gets included/executed once.  Unfortunately, bash doesn't
+# usually distinguish between values that are unset and values that are null.
+# To work around that, we declare TRAPFUNCS to be a one-element array right at
+# the start, but that one element is : which is defined to do nothing.
+
+if [ ${#TRAPFUNCS[@]} = 0 ]; then
+        TRAPFUNCS=(:)
+
+        push_trapfunc () {
+                TRAPFUNCS[${#TRAPFUNCS[@]}]="$@"
+        }
+
+        execute_trapfuncs () {
+                for i in "${TRAPFUNCS[@]}"; do
+                        $i
+                done
+        }
+
+        trap execute_trapfuncs EXIT
+fi