diff --git a/tests/pillar/compute_single.sls b/tests/pillar/compute_single.sls
index 08250ba..211a60e 100644
--- a/tests/pillar/compute_single.sls
+++ b/tests/pillar/compute_single.sls
@@ -7,6 +7,7 @@
     vncproxy_url: openstack:6080
     vnc_keymap: en-gb
     resume_guests_state_on_host_boot: False
+    preallocate_images: space
     cpu_mode: custom
     libvirt:
       cpu_model: IvyBridge