Note that for IDP 3, all the test scripts have been modified to set the content type header to text/xml. This is because curl by default will set an inappropriate content type application/x-www-form-urlencoded) that IDP 2 would tolerate, but IDP 3 will not.
The content type is currently set to application/vnd.paos+xml (ECP.swift#L193), so I'm not sure how IDP3 will respond to that.
See https://wiki.shibboleth.net/confluence/display/IDP30/IDP3+ECP+with+Tomcat+and+Apache-Managed+Authentication
The content type is currently set to
application/vnd.paos+xml
(ECP.swift#L193), so I'm not sure how IDP3 will respond to that.