Docker Multi-stage Builds and Test results - How to get them?

Question

Apparently, all articles I found about multi-stage builds cover the happy path.

But how to get the test results (e.g. unit or acceptance tests) out of a builder-container when something fails?

Answer 1

I think that you can do things like

 docker build --target test -t <your_test_image> .

Then you could just run this image with volumes attached and gather results...

More here.