To untaint my nodes, my scripts use ...

# kubectl taint nodes --all node-role.kubernetes.io/master-

but I want to deliberately taint my node to test this untaint functionality. I tried this variant and it works fine ...

# kubectl taint nodes foo foo=DoNotSchedulePods:NoExecute 
# kubectl taint nodes foo foo:NoExecute-   
node/foo untainted

but I can't see how to set up so I can test the specific taint that I need to get rid of. I tried e.g.

# kubectl taint nodes foo foo=node-role.kubernetes.io/master     
error: unknown taint spec: foo=node-role.kubernetes.io/master  

How to put it into situation where I can test the aforementioned untainted command?