Create a directory called testcertificates
Download the file DanID Test (gyldig) under Virksomhedscertifikater from https://www.nets.eu/dk-da/kundeservice/nemid-tjenesteudbyder/NemID-tjenesteudbyderpakken/Pages/OCES-II-certifikat-eksempler.aspx
Convert it to pem file openssl pkcs12 -in VOCES_gyldig.p12 -out certificate.cer -nodes use the password Test1234
Now open certificate.cer in your favorite editor
Find the line that begins with -----BEGIN PRIVATE KEY----- copy from here until -----END PRIVATE KEY-----
Save the content as test_private.pem in testcertificates directory
Find the FIRST line that begins with -----BEGIN CERTIFICATE----- copy from here until the FIRST -----END CERTIFICATE-----
Save the content as test_public.pem in testcertificates directory
Now fire up a PHP server, and run test.php
With PHP internal server it can be done with php -S localhost:8000 -t .