The instant vector selector can be expressed as
namespace="test1"to match labelnamespaceexactly equal to"test1"<no selector on namestapce>to match all values ofnamespacenamespace=~"test1|test2"to match labelnamespacewith given regex
You made a mistake: you used a regex "test1[test2" with an exact match (=) instead of regex match (=~).
Correct expression would be:
kube_resourcequota{resource="count/deployments.apps",type="hard",namespace=~"test1|test2"}