[folks] tests: avoid using dconf

[Travis Reitter <treitter src gnome org>]

commit 71f6f79f7a9e95078d2e5a0ad2a48652197339a9
Author: Simon McVittie <simon mcvittie collabora co uk>
Date:   Mon Mar 24 14:16:11 2014 +0000

    tests: avoid using dconf
    
    tests/eds/perf reliably fails for me with this warning:
    
    dconf-WARNING **: failed to commit changes to dconf: 
GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name ca.desrt.dconf was not provided by any 
.service files
    
    and in any case we shouldn't be changing the user's real configuration.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=726973

 tests/lib/test-case.vala |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/tests/lib/test-case.vala b/tests/lib/test-case.vala
index 8a93a56..1eeb430 100644
--- a/tests/lib/test-case.vala
+++ b/tests/lib/test-case.vala
@@ -137,6 +137,9 @@ public abstract class Folks.TestCase : Object
 
       debug ("setting up in transient directory %s", transient);
 
+      /* Don't try to use dconf */
+      Environment.set_variable ("GSETTINGS_BACKEND", "memory", true);
+
       /* GLib >= 2.36, and various non-GNOME things, obey this. */
       Environment.set_variable ("HOME", transient, true);
       /* GLib < 2.36 in Debian obeyed this (although upstream GLib < 2.36