Add completion test on centos

It was reported in
helm/helm#7304
that centos does not support 'tail +2' but must use the form
'tail -n +2'.

This commits adds a test for centos to prevent any regressions with
centos

Signed-off-by: Marc Khouzam <marc.khouzam@montreal.ca>

scripts/completion-tests/test-completion.sh

@@ -146,6 +146,24 @@ docker run --rm \
            -e COMP_DIR=${COMP_DIR} \
            ${BASH3_IMAGE} bash -c "source ${COMP_SCRIPT}"
 
+########################################
+# Bash centos completion tests
+# https://github.com/helm/helm/pull/7304
+########################################
+BASH_IMAGE=completion-bash-centos
+
+echo;echo;
+docker build -t ${BASH_IMAGE} - <<- EOF
+   FROM centos
+   RUN yum install -y bash-completion which
+EOF
+docker run --rm \
+           -v ${COMP_DIR}:${COMP_DIR} \
+           -e ROBOT_HELM_V3=${ROBOT_HELM_V3} \
+           -e ROBOT_DEBUG_LEVEL=${ROBOT_DEBUG_LEVEL} \
+           -e COMP_DIR=${COMP_DIR} \
+           ${BASH_IMAGE} bash -c "source ${COMP_SCRIPT}"
+
 ########################################
 # Zsh completion tests
 ########################################