chore(tests): drop docker, and use travis/ava to test in multiple versions of node and npm

[DrewML]

It works! Currently have it testing against npm versions 3.8.7 and 3.10.5 in node 5 and 6, but we can easily update .travis.yml to add more at any time.

Work done:

1. Converted test cases in runtests.sh to test cases in test.js
2. Setup ava for testing
3. Removed docker-related config
4. Enabled testing in TravisCI, with multiple versions of node and npm

Opinionated Changes (might be worth discussing):

1. I wrote some code for the sinopia setup, but I ended up stopping because I'm questioning how much value it provides. Based on this PR, it seems like this was added to reduce the dependency on npm. But, unless I'm mistaken, sinopia is still going to be proxying out to npm for dependencies, unless they're stored in the repo and linked to sinopia's storage. (If we do decide to drop sinopia, I have some commented out code I'll need to remove).
2. I renamed the test folder to testing. This was purely to get around some conflicts with ava's automatic discovery of test files that match a certain pattern. Renaming the directory seemed like the path of least resistance, but we can also override the pattern ava uses to discover test files, if you prefer.
3. I added the execa package to make life a bit easier when working with child_process and promises.
4. Some of the utilities in testutil.js could also be shell scripts, but my thought process was, if done this way (cross-platform utils), we might be able to get testing setup on Windows using Appveyor at some point if it was desired.

I'm open to any feedback you have to offer :). If you do decide to accept the PR, I'll need to update CONTRIBUTING.md with updated instructions for testing locally.

[JamieMason]

Thanks so much @DrewML, running this now.

[JamieMason]

Great work @DrewML, being able to run all kinds of node/npm combinations on Travis will be a huge help.

I've gone through and made a TODO list, but they're basically either just things I agree about or minor points about the coding style I like to keep in this project;

• [x] Yeah let's remove Sinopia, it was an optimisation mainly but causes more problems than it solves I think.
• [x] nice, looks like we could replace cross-spawn with execa and also get rid of some other awkwardness to do with spawning.
• [x] Would be keen to keep test/ as that's fairly standard for a lot of projects, we could move testing/package.json to test/lib/package.json or similar, as the Sinopia stuff is going.
• [x] I'd like the use of ES6 to be consistent in the test files (test.js uses it but testutil.js does not) I see why this is now, Ava doesn't transpile test imports.
• [x] Would be keen to get test.js and testutil.js moved to the test/ folder.
• [x] Group imports/requires at the top of files by node modules, 3rd party modules, modules etc and A-Z order them (just a style thing I've been doing here).
• [x] testutil.js would be test-util.js by convention.

I'm free at the moment so am happy to pick this up. Thanks a lot,

Jamie

[DrewML]

I'm free at the moment so am happy to pick this up. Thanks a lot,

Totally up to you. If not, I can clean all these up tonight.

[JamieMason]

I just pushed up your work with the above changes applied to it, to https://github.com/JamieMason/shrinkpack/commits/DrewML-travis-tests. Please let me know of anything you'd like to add or change, and thanks again for this big improvement to the project.

[DrewML]

@JamieMason Nice! Changes look good to me

[JamieMason]

Released in 0.16.1 🎆