Add support for --repeat to mix test

[azizk]

Environment

• Elixir & Erlang/OTP versions (elixir --version): Elixir 1.12.0 (compiled with Erlang/OTP 24)
• Operating system: Linux

Current behavior

Mix doesn't support a --repeat option, which makes repeating the previously executed tests difficult or inconvenient.

Expected behavior

I'm missing such an option because:

• in an editor it's pretty simple to bind a shortcut to mix test --repeat which aids in TDD
• in the CLI it's practical to have mix repeat the tests if all succeeded after a mix test --failed
• likewise after a mix test --stale or any other similar command

[azizk]

Would love to see this implemented. ❤️ Maybe I could do it but I don't think I'd be fast. I have no clue about the mix code base.

[wojtekmach]

Please send feature proposals to the elixir-lang-core mailing list :)

[azizk]

Sorry, my bad. :)

[josevalim]

Closing pending the mailing list discussion. I also think this may be implemented as mix test --failed && mix test? So it is important to discuss that too.