Fix: Test bug - we have to force the right Docker image to be used for the tests. Trusty works.
diff --git a/utils/docker/Dockerfile b/utils/docker/Dockerfile
index 2c1bda6..47b0ed0 100644
--- a/utils/docker/Dockerfile
+++ b/utils/docker/Dockerfile
@@ -12,6 +12,9 @@
 WORKDIR /son-emu
 COPY . /son-emu/
 
+# ensure that we have the right docker image for tests available
+RUN docker run --rm ubuntu:trusty
+
 RUN cd /son-emu/ansible \
     && ansible-playbook install.yml \
     && cd /son-emu \