Tiny Robots Cover Module

A Mix test coverage tool used by Tiny Robots.

Rbtz.CoverModule is a fork of Elixir's built-in Mix.Tasks.Test.Coverage with a few additional features layered on top. It is a drop-in replacement — all upstream options (summary, threshold, ignore_modules, output, export, local_only) behave identically, so switching is just a one-line tool: change in your mix.exs.

Hides fully-covered modules from the summary table

Only modules below 100% appear in the per-module breakdown — the total line still reflects the full project. Keeps the summary focused on what needs attention as coverage grows.

Quieter HTML generation

When used with Mimic (or anything else that restores modules between tests), :cover's HTML phase floods stdout with Redefining module ... / Restoring module ... notices. Rbtz.CoverModule redirects the :cover_server group leader during HTML generation only, suppressing that noise while leaving the summary table, threshold result, and regular test output untouched.

Installation

Add rbtz_cover_module to your mix.exs dependencies:

def deps do
  [
    {:rbtz_cover_module, "~> 0.1", only: [:test], runtime: false}
  ]
end

Run mix deps.get.

Usage

Set it as the tool: in your test_coverage: config:

def project do
  [
    # ...
    test_coverage: [
      tool: Rbtz.CoverModule,
      summary: [threshold: 100],
      ignore_modules: [
        MyApp.Application,
        MyApp.Release,
        ~r/^MyApp\.Generated\./
      ]
    ]
  ]
end

Then run as usual:

mix test --cover                         # inline summary + HTML in cover/
mix test --cover --export-coverage unit  # export coverdata for later merge
mix test.coverage                        # merge exported coverdata

Configuration

Rbtz.CoverModule accepts the same options as Elixir's built-in coverage tool. See the upstream Mix.Tasks.Test.Coverage docs for the full option list (summary, threshold, ignore_modules, output, export, local_only). Just set tool: Rbtz.CoverModule.

Credits

Forked from Elixir's Mix.Tasks.Test.Coverage. Used in production across Tiny Robots projects.

License

MIT. See LICENSE.