diff --git a/Docker/lofar-ci/Dockerfile_ci_sas b/Docker/lofar-ci/Dockerfile_ci_sas
index 46ee2e412e2fa1fb03fb23da5cf035e1838b3b53..6d23693123c650c3ee9173f4d3e158d00b7f5d8b 100644
--- a/Docker/lofar-ci/Dockerfile_ci_sas
+++ b/Docker/lofar-ci/Dockerfile_ci_sas
@@ -16,7 +16,7 @@ RUN yum erase -y postgresql postgresql-server postgresql-devel && \
     cd /bin && ln -s /usr/pgsql-9.6/bin/initdb && ln -s /usr/pgsql-9.6/bin/postgres
 ENV PATH /usr/pgsql-9.6/bin:$PATH 
 
-RUN pip3 install cython kombu lxml requests pygcn xmljson mysql-connector-python python-dateutil Django==3.0.9 djangorestframework==3.11.1 djangorestframework-xml ldap==1.0.2 flask fabric coverage python-qpid-proton PyGreSQL numpy h5py psycopg2 testing.postgresql Flask-Testing scipy Markdown django-filter python-ldap python-ldap-test ldap3 django-jsonforms django-json-widget django-jsoneditor drf-yasg flex swagger-spec-validator django-auth-ldap mozilla-django-oidc jsonschema comet pyxb==1.2.5 graphviz isodate astropy packaging django-debug-toolbar pymysql astroplan SimpleWebSocketServer
+RUN pip3 install cython kombu lxml requests pygcn xmljson mysql-connector-python python-dateutil Django==3.0.9 djangorestframework==3.11.1 djangorestframework-xml ldap==1.0.2 flask fabric coverage python-qpid-proton PyGreSQL numpy h5py psycopg2 testing.postgresql Flask-Testing scipy Markdown django-filter python-ldap python-ldap-test ldap3 django-jsonforms django-json-widget django-jsoneditor drf-yasg flex swagger-spec-validator django-auth-ldap mozilla-django-oidc jsonschema comet pyxb==1.2.5 graphviz isodate astropy packaging django-debug-toolbar pymysql astroplan SimpleWebSocketServer websocket_client
 
 #Viewflow package 
 RUN pip3 install django-material django-viewflow
diff --git a/SAS/TMSS/services/websocket/test/CMakeLists.txt b/SAS/TMSS/services/websocket/test/CMakeLists.txt
index 2d2c7976cedf12376f9aaef97e0383c9a805bb5b..251b9057f5953b2f0450adb9ce8e8d8497cfb99a 100644
--- a/SAS/TMSS/services/websocket/test/CMakeLists.txt
+++ b/SAS/TMSS/services/websocket/test/CMakeLists.txt
@@ -1,6 +1,9 @@
 # $Id: CMakeLists.txt 32679 2015-10-26 09:31:56Z schaap $
 
 if(BUILD_TESTING)
+    include(FindPythonModule)
+    find_python_module(websocket REQUIRED)            # sudo pip3 install websocket_client
+
     include(LofarCTest)
 
     lofar_add_test(t_websocket_service)