Add test suite

[itsdalmo]

Based on the work in: https://github.com/buildkite/lifecycled/pull/50

I just decided to rewrite with inspiration from the PR above, to get a basic test suite up and running. In the process I figured it was prudent to do the following:

• Move main.go to cmd/main.go so that we can use package names to ensure that we are testing the public interface (i.e. whats usable from main.go) in our tests.
• Create a logrus.Logger to pass around, so that we can use NullLogger in the tests.
• Pass log.Entry to some listener and handler methods, so that we can propagate fields.
• Removed all log entries from the Queue methods (instead logging these from the listener itself).
• Return the TerminationNotice from daemon.Start() so that we have a return value to test in our test suite. To not bloat main.go I decided to make a Config struct and have the lifecycled.New() and lifecycled.NewDaemon() functions do more of the boilerplate setup.

With the above in place, I wrote three basic tests to validate the behaviour of the daemon, with the goal of ignoring implementation details as far as possible. So for future PR's etc we should be able to run tests to catch things like Queues not being cleaned up.

Possible improvements:

• Use the hook returned by the NullLogger to print the log entries when/if tests fail. Since we are handling a lot of errors by logging them, this would make it a lot easier to debug failing tests.

Let me know what you think 👍

[itsdalmo]

Thoughts on this @lox?

[lox]

Apologies, I've been sick! 😷Will review this tomorrow!

[itsdalmo]

NP! Get well soon 🙌

[lox]

Can we go with /cmd/lifecycled/main.go so that go install ./cmd/lifecycled does the right thing?

[itsdalmo]

@lox - Thanks for the review! Have moved the binary, and feel confident that RFC3339 should work here - but we should test it in the wild before making a 3.0 release - are you up for that? 😄

edit: Just caught one error I had made; lifecycled.Config accepts a SpotListenerInterval, which was not being set in main.go and therefore defaulted to 0 and crashed the binary on startup. Fixed now, and everything works just dandy with autoscaling termination notices (need you to test spot terminations if possible) 👍

[itsdalmo]

What do you think @lox - is this ready to be merged?

[lox]

Yeah, let's merge it. Sorry for the delay.