Npm (5) install will override the symlinked addon under test

[simonihmig]

Not a bug here, but in npm itself: npm/npm#17287

Lost quite some time because of this, so mentioning this here in case others get bitten by this. ember-cli-addon-tests will symlink the addon under test into node_modules of the temporary app, but if you call npm install afterwards (e.g. by calling app.run('npm', 'install')), npm 5 will remove the symlink and install the addon from the npm registry (which is probably not the same code that you are working on). Does not happen with npm 3.

[kellyselden]

All I have to say is WTF.

[mansona]

Ok so I've done some investigation into this and I don't really know how to proceed. The main issue is that the link needs to be the last thing that is done after all npm install steps.

@simonihmig you are right saying this is a known issue in npm but the main issue is this one npm/npm#10343 which is tagged with big-bug so it's unlikely that we'll get an "out of the box" fix any time soon, although I happen to know that npm@6 had an internal refactoring that was specifically designed to address issues like this.

I will create a PR to show my work so far, although it is specifically related to kaliber5/ember-fastboot-addon-tests#21