humanmade/wp-simple-saml
https://github.com/humanmade/wp-simple-saml/wiki/Testing-SSO-locally
node.js - How do I set up a local test SAML2.0 Identity Provider? - Stack Overflow
https://stackoverflow.com/questions/24779000/how-do-i-set-up-a-local-test-saml2-0-identity-provider