diff --git a/.gitlab/ci/ubuntu1604.yml b/.gitlab/ci/ubuntu1604.yml
index ca4e71d53..d0adead93 100644
--- a/.gitlab/ci/ubuntu1604.yml
+++ b/.gitlab/ci/ubuntu1604.yml
@@ -83,6 +83,9 @@ test:ubuntu1604_gcc48:
     #env flags to allow openmpi to run as root user
     OMPI_ALLOW_RUN_AS_ROOT: 1
     OMPI_ALLOW_RUN_AS_ROOT_CONFIRM: 1
+    #mpi location so that `built_against_test_install` tests
+    #pass
+    CMAKE_PREFIX_PATH: "/opt/openmpi/"
 
   dependencies:
     - build:ubuntu1604_gcc48