test-dbus.py: more reliable process handling

First, kill all running syncevo-dbus-server instances. Having
one running was one way how the tests could have failed because
it wasn't running with the right environment.

Second, use files for output instead of in-memory pipes. The latter
might have caused deadlocks when a process writes large amount of
data.

syncevo.log and dbus.log in the current directory are used. The
additional benefit is that these files can be read while the test
runs, for example when it is deadlocked for some other reason.

Third, when syncevo-dbus-server returns with a non-zero error code,
give dbus-monitor time to settle down before stopping it. Otherwise
the final D-Bus traffic might not get recorded.

test/test-dbus.py

@@ -67,6 +67,9 @@ class DBusUtil:
         test-dbus/[data|config|cache] which are removed before each
         test."""
 
+        kill = subprocess.Popen("sh -c 'killall -9 syncevo-dbus-server >/dev/null 2>&1'", shell=True)
+        kill.communicate()
+
         env = copy.deepcopy(os.environ)
         if own_xdg:
             shutil.rmtree(xdg_root, True)
@@ -74,8 +77,10 @@ class DBusUtil:
             env["XDG_CONFIG_HOME"] = xdg_root + "/config"
             env["XDG_CACHE_HOME"] = xdg_root + "/cache"
 
+        dbuslog = "dbus.log"
+        syncevolog = "syncevo.log"
         pmonitor = subprocess.Popen(monitor,
-                                    stdout=subprocess.PIPE,
+                                    stdout=open(dbuslog, "w"),
                                     stderr=subprocess.STDOUT)
         if debugger:
             print "\n%s: %s\n" % (self.id(), self.shortDescription())
@@ -97,9 +102,10 @@ class DBusUtil:
         else:
             pserver = subprocess.Popen(server,
                                        env=env,
-                                       stdout=subprocess.PIPE,
+                                       stdout=open(syncevolog, "w"),
                                        stderr=subprocess.STDOUT)
-            pserver.stdout.readline()
+            while os.path.getsize(syncevolog) == 0:
+                time.sleep(1)
 
         numerrors = len(result.errors)
         numfailures = len(result.failures)
@@ -112,12 +118,16 @@ class DBusUtil:
 
         if not debugger:
             os.kill(pserver.pid, signal.SIGTERM)
-        serverout, dummy = pserver.communicate()
+        pserver.communicate()
+        serverout = open(syncevolog).read()
+        if pserver.returncode and pserver.returncode != -15:
+            hasfailed = True
         if hasfailed:
             # give D-Bus time to settle down
             time.sleep(1)
         os.kill(pmonitor.pid, signal.SIGTERM)
-        monitorout, dummy = pmonitor.communicate()
+        pmonitor.communicate()
+        monitorout = open(dbuslog).read()
         report = "\n\nD-Bus traffic:\n%s\n\nserver output:\n%s\n" % \
             (monitorout, serverout)
         if pserver.returncode and pserver.returncode != -15: