Fail tests on lint warnings
Fail tests on lint warnings

Both for the sake of clean code, and catching some more serious problems
like unscoped variables. Unfortunately this isn't the default.

boffbowsh/ci-puppet,alphagov/ci-puppet,alphagov/ci-puppet,boffbowsh/ci-puppet,alphagov/ci-puppet,boffbowsh/ci-puppet,alphagov/ci-puppet,boffbowsh/ci-puppet