Oxygen has a WSDL SOAP Analyser which allows easy testing of web services. Unfortunately, I had trouble because my service was deployed with HTTPS, using a self-signed certificate.

There are instructions at http://www.oxygenxml.com/doc/ug-editor/tasks/import-https-server-certificate.html to import the certificate into the JVM used by Oxygen but this didn't work for me.

An alternative solution which did work for me was to upgrade to Oxygen 15.1. This has an option to allow all security certificates to be accepted, even if they are invalid, which is good enough for my testing.

To access this option, use Options/Preferences/Network Connection Settings/HTTP(S) & WebDAV, and enable Automatically accept a security certificate, even if invalid.