Method defined as testMethod do not support web service callouts, test skipped

You need to call Test.setMock(...) in your test class once you've implemented the required interfaces to prevent this particular error message.

You shouldn't need to use Test.isRunningTest() to test your call outs (and doing so give you untestable code).

you may want to include test.isrunningtest in your actual callout class to check you are not going to run actual callout and only test mock. take a look on this thread

Testing HttpCallout with HttpCalloutMock and UnitTest Created Data