Webtest failure due to invalid payment processor config

In 4.7 the code that loads the payment processors won't load 'invalid' processors onto pages - ie. processors that fail the checkConfig() function on their class.

I see a webtest failing

https://test.civicrm.org/job/CiviCRM-WebTest-Matrix/CIVIVER=master,label=test-ubu1204-1/lastCompletedBuild/testReport/%28root%29/WebTest_Member_OnlineMembershipRenewTest/testOnlineMembershipRenew/

WebTest_Member_OnlineMembershipRenewTest::testOnlineMembershipRenew
"Fatal Error" encountered at http://build-3.l/civicrm/contribute/transact?reset=1&id=2
Error Message: A payment processor configured for this page might be disabled (contact the site administrator for assistance).

/srv/buildkit/build/build-3/sites/all/modules/civicrm/tests/phpunit/CiviTest/CiviSeleniumTestCase.php:2388
/srv/buildkit/build/build-3/sites/all/modules/civicrm/tests/phpunit/CiviTest/CiviSeleniumTestCase.php:225
/srv/buildkit/build/build-3/sites/all/modules/civicrm/tests/phpunit/WebTest/Member/OnlineMembershipRenewTest.php:102
/srv/buildkit/build/build-3/sites/all/modules/civicrm/tools/scripts/phpunit:80

And I suspect this could be fixed by fixing the webtest to create a valid processor - ie. in

https://github.com/civicrm/civicrm-core/blob/feb02c31f51d8b7a0a88cf9d436160e9399e8828/tests/phpunit/CiviTest/CiviSeleniumTestCase.php#L828-828

However, I had another go at getting webstests to work for me today & have abandoned them again