What the hell does Litmus mean? Is it a test in this context?

Ok today I am just stupid, I have heard of the Litmus test so that is what I assume this is.

If I could ask one question:

Do you require trust be earned or give trust until it is lost?

This doesn’t decide if I want to be a friend, I need all the friends I can get, it more tells me where I stand with them and how I need to treat the friendship