need a docker image to mimic the travis environment

[gonewest818]

While resolving other travis-related issues, it became clear the project needs a dev docker environment that can run locally on one's laptop but emulates what is going on in travis. This would be a place to debug not only issues with travis, but also a way to run "make test" and "make test-bytecomp" locally.

[bbatsov]

That would be nice indeed.

[timvisher]

I think it's possible to use TravisCI's images? https://medium.com/google-developers/how-to-run-travisci-locally-on-docker-822fc6b2db2e

[gonewest818]

Interesting. I hadn't seen that one before. But for sake of simplicity, all I'm doing is building a Dockerfile and a few convenience scripts such that you can build a docker container that runs and drops you into a bash shell.

So it's an emulation of the build environment that Travis uses, but it doesn't at all try to emulate the way the jobs are launched in Travis.

https://github.com/gonewest818/cider/blob/2144-docker-image/Dockerfile

You can run that container with your source tree mounted such that you can edit as you like from your host computer but then switch to the docker shell and make clean test to confirm tests. I'm preinstalling emacs-{25.3,26-pretest,git-snapshot}-travis so you can toggle emacs versions and retest evm use emacs-26-pretest-travis; make elpaclean test.

Still a work in progress.