support binary files in generated_file_test

[longlho]

🚀 feature request

Relevant Rules

generated_file_test

Description

We have the use case of checking in assets like fonts/png/tar files and it'd be great if generated_file_test supports binary files as well. Right now it reads file as utf-8 encoding and during write as well which messes stuff up.

Happy to put in a PR if you want.

Describe the solution you'd like

generated_file_test supports binary files as well.

Describe alternatives you've considered

Write my own implementation?

[alexeagle]

We have is_binary in the repo already, but it has false positives.

The simplest answer is to use bazel-skylib directly. I added a failure_message attribute to diff_test https://docs.aspect.dev/bazelbuild/bazel-skylib/1.1.1/docs/diff_test.html
so you can just use the pattern directly, paired with an sh_binary to copy the file.
See https://blog.aspect.dev/bazel-can-write-to-the-source-folder

[longlho]

thanks for the pointer. That works!