Update test.mdx

Author: HenrietteBossen

docs/online/development-guide/test.mdx

@@ -5,4 +5,8 @@ import TestApp from '/docs/shared-blocks/_test-app.mdx';
 
 # Test
 
-Please see: https://developer.mobilepay.dk/docs/online/transition-to-one-platform#test-availability
+* Credentials: During onboarding you will receive a client id and client secret for test. You will also receive a test user. If needed you can request a new by contacting [email protected]. Please state if you need a DK or FI user.
+* Endpoints: The test endpoints can be found in the [API specification](https://developer.mobilepay.dk/api/online).
+* Test app: Download and login instructions for the test app can be found [here](https://developer.vippsmobilepay.com/docs/test-environment/#test-apps).
+
+Note: It is not possible to add your own cards to the test users. Instead you can utilize magic numbers documented [here](https://developer.vippsmobilepay.com/docs/APIs/psp-api/vipps-psp-api/#magic-numbers-for-emvco-tokens). Note that the documentation for the magic numbers are part of the Vipps PSP documentation. But it is only the section about magic numbers that are relevant for your MobilePay Online test, the rest is related to Vipps PSP solution. For MobilePay Online you must still follow the existing [MobilePay Online documentation](https://developer.mobilepay.dk/docs/online).