Feature environment passthru

[jsleeio]

kubetest is ace! Thankyou!

Added an --env option to make whitelisted environment variables available to Skylark tests via an additional global environment. This will be useful in my work to pass through certain metadata into the testsuite — initially to supply information for tests concerning resource names, but I'm 100% sure there'll be further applications for it later.

I updated the example tests to demonstrate this feature.

Example invocation:

$ MINREPLICAS=8 bin/darwin/amd64/kubetest -e MINREPLICAS -t examples/tests examples/rc.yaml --verbose
INFO setting up environment passthrough            envList=MINREPLICAS
INFO environment variable                          MINREPLICAS=8
INFO examples/rc.yaml should not use latest images
WARN examples/rc.yaml ReplicationController should have at least 8 replicas

Environment variables with an empty value are not passed through at all, with the intention being that Skylark code should not have to make any more effort than if "FOO" in environment: ...

[jsleeio]

Looks like there was some kind of build-environment problem with TravisCI? 😢