Be more robust against cataclysmic test failures

Previously, if MC never claimed its bus names (because it was crashing
on startup, for instance), the exception in the test initialization code
wasn't caught. This means nothing would ever quit the Twisted mainloop,
and the (failed) test would sit there forever.

This patch ensures that the test exits uncleanly if this happens.

1 files changed, 17 insertions, 13 deletions

diff --git a/tests/twisted/mctest.py b/tests/twisted/mctest.py
index fee227f3..8a37e914 100644
--- a/tests/twisted/mctest.py
+++ b/tests/twisted/mctest.py
@@ -66,6 +66,16 @@ def install_colourer():
     sys.stdout = Colourer(sys.stdout, patterns)
     return sys.stdout
 
+def wait_for_name(queue, bus, name):
+    if not bus.name_has_owner(name):
+        queue.expect('dbus-signal', signal='NameOwnerChanged',
+                predicate=lambda e: e.args[0] == name and e.args[2])
+
+def wait_for_mc(queue, bus, params):
+    mc = make_mc(bus, queue.append, params)
+    wait_for_name(queue, bus, cs.AM)
+    wait_for_name(queue, bus, cs.CD)
+    return mc
 
 def exec_test_deferred (fun, params, protocol=None, timeout=None,
         preload_mc=True):
@@ -81,23 +91,17 @@ def exec_test_deferred (fun, params, protocol=None, timeout=None,
 
     bus = dbus.SessionBus()
     queue.attach_to_bus(bus)
-    if preload_mc:
-        mc = make_mc(bus, queue.append, params)
-
-        try:
-            bus.get_name_owner(cs.AM)
-        except dbus.DBusException, e:
-            queue.expect('dbus-signal', signal='NameOwnerChanged',
-                    predicate=lambda e: e.args[0] == cs.AM and e.args[2])
+    error = None
 
+    if preload_mc:
         try:
-            bus.get_name_owner(cs.CD)
-        except dbus.DBusException, e:
-            queue.expect('dbus-signal', signal='NameOwnerChanged',
-                    predicate=lambda e: e.args[0] == cs.CD and e.args[2])
+            mc = wait_for_mc(queue, bus, params)
+        except Exception, e:
+            import traceback
+            traceback.print_exc()
+            os._exit(1)
     else:
         mc = None
-    error = None
 
     try:
         fun(queue, bus, mc)