Added postinstall script

[ghost]

Description

Added post install task

Issues

• resolves Trails should be tested with yarnpkg in addition to npm #249

[jaumard]

Hi :)
Yarn.lock shouldn't be under git in my opinion, it should be on git ignore file.
Also we don't want to run tests after install at all. And you command use npm where the issue talk about yarn ?? Don't see how this can fix the issue.

[ghost]

Issue Description #249
All trails tests need to be run from a yarn install as well as npm

So what tests should be run after a yarn/npm install?

On topic of the yarn.lock: https://yarnpkg.com/en/docs/yarn-lock#toc-check-into-source-control

All yarn.lock files should be checked into source control (e.g. git or mercurial). This allows Yarn to install the same exact dependency tree across all machines, whether it be your coworker’s laptop or a CI server.

[jaumard]

Yes trails tests, this means tests on travisCI and appVeyor should install/launch tests once with npm and once with yarn to test both.

About the yarn.lock now I'm sure it doesn't have to be on git (thanks for the link). Here we don't want to have all same package version because it's an open framework not a project. By setting it on git you bypass package dependencies rules and we don't want this. It sure make sense on real project and it's a great feature!

[ghost]

Ok, then i misunderstood the requirements.

[jaumard]

No problem, @tjwebb correct me if I'm wrong

[tjwebb]

Yarn.lock shouldn't be under git in my opinion, it should be on git ignore file.

This could go either way. I think the only issue here is that, if the yarn.lock file is checked in, then yarn and npm install will probably install different versions of stuff, unless we also maintain an npm shrinkwrap file that is identical to the yarn.lock file. I think overall this would actually be good, but we'd need to implement some sort of management system to verify this. I don't want to do this by hand...