Adding testing infos in README

Author: perki

components/pryv/README.md

@@ -696,6 +696,22 @@ just test <component> [...params]
 - Extra parameters at the end are passed on to [Mocha](https://mochajs.org/) (default settings are defined in `.mocharc.js` files)
 - Replace `test` with `test-debug`, `test-cover` for common presets
 
+By default tests are done against [Pryv Lab](https://www.pryv.com/pryvlab/) with serviceInfo Url `https://reg.pryv.me/service/info`.
+
+To run test suite against another Pryv instance use `TEST_PRYVLIB_SERVICEINFO_URL` environement variable.  
+
+Exemple:
+```
+TEST_PRYVLIB_SERVICEINFO_URL="https://reg.${DOMAIN}/service/info" just test all
+```
+
+To test **in-development** api-server components, e.g. Open-Source or Entreprise. `TEST_PRYVLIB_DNSLESS_URL` may be used.
+
+Exemple:
+```
+TEST_PRYVLIB_DNSLESS_URL="http://l.rec.la:3000/ just test all
+```
+
 #### Browser
 
 Assuming browser files have been built (see above):