Add coverage reporting

[hauleth]

No description provided.

[marc0s]

Hi, how would you like this to be done? Calling mix test --cover from some Github action? Or maybe using ExCoveralls?

[hauleth]

I was thinking about ExCoveralls or Covertool and upload them to CodeCov.io

[marc0s]

Ok! Will have a look into it.

[marc0s]

I have configured mix_unused to depend on ExCoveralls but I'm unable to run it because the following errors. I've done the same exact steps in another personal project without any troubles.

➜ MIX_ENV=test mix coveralls
...............................................

Finished in 2.7 seconds (0.1s async, 2.5s sync)
6 doctests, 41 tests, 0 failures

Randomized with seed 681095

** (FunctionClauseError) no function clause matching in IO.chardata_to_string/1    
    
    The following arguments were given to IO.chardata_to_string/1:
    
        # 1
        nil
    
    Attempted function clauses (showing 2 out of 2):
    
        def chardata_to_string(string) when is_binary(string)
        def chardata_to_string(list) when is_list(list)
    
    (elixir 1.12.1) lib/io.ex:607: IO.chardata_to_string/1
    (elixir 1.12.1) lib/path.ex:422: Path.dirname/1
    (excoveralls 0.14.3) lib/excoveralls/cover.ex:21: ExCoveralls.Cover.module_path/1
    (excoveralls 0.14.3) lib/excoveralls/stats.ex:54: ExCoveralls.Stats.add_counts/4
    (elixir 1.12.1) lib/enum.ex:2356: Enum."-reduce/3-lists^foldl/2-0-"/3
    (excoveralls 0.14.3) lib/excoveralls/stats.ex:28: ExCoveralls.Stats.report/1
    (excoveralls 0.14.3) lib/excoveralls.ex:47: ExCoveralls.execute/2
    (mix 1.12.1) lib/mix/tasks/test.ex:520: Mix.Tasks.Test.do_run/3
    (mix 1.12.1) lib/mix/task.ex:394: anonymous fn/3 in Mix.Task.run_task/3
    (excoveralls 0.14.3) lib/mix/tasks.ex:54: Mix.Tasks.Coveralls.do_run/2
    (mix 1.12.1) lib/mix/task.ex:394: anonymous fn/3 in Mix.Task.run_task/3
    (mix 1.12.1) lib/mix/cli.ex:84: Mix.CLI.run_task/2
    (elixir 1.12.1) lib/code.ex:1261: Code.require_file/2

Do you think that this might be related to the way mix_unused hooks itself into the compiler options or some of that stuff?

The culprit of the error is that while running mix coveralls the output of Mix.Project.config_files() returns a list like this one, without mix.es:

["/home/marc0s/Projects/Personal/mix_unused/_build/dev/.mix/compile.lock"]

What I find strange is that I'm running all mix tasks with MIX_ENV=test and the path above contains _build/dev instead.

Any hint would be appreciated.

Thanks

[hauleth]

So you have branch that I can look into?

[marc0s]

Just pushed to https://github.com/marc0s/mix_unused/tree/25-coverage-report

Thanks

[marc0s]

For running the coverage analysis and report, run MIX_ENV=test mix coveralls

(branch updated with before missing coveralls.json file)

[hauleth]

It seems like bug in ExCoveralls triggered by the fact that we are using Mix.Project.in_project/3 to run some tests against other Mix projects.

[hauleth]

This patch to lib/excoveralls/path_reader.ex seems to fix it:

<       :error -> Mix.Project.config_files() |> Enum.find(&(&1 =~ ~r/mix.exs/)) |> Path.dirname()
---
>       :error -> File.cwd!()

And as mix must be ran from the same directory as the mix.exs file is, it should work in all cases (IIRC it will work in umbrella as well, as Mix changes directory before running actions for sub projects).

[hauleth]

@marc0s see parroty/excoveralls#271

[marc0s]

Looks like your fix makes it work:

➜ MIX_ENV=test mix coveralls
Compiling 8 files (.ex)
Generated mix_unused app
...............................................

Finished in 2.5 seconds (0.1s async, 2.4s sync)
6 doctests, 41 tests, 0 failures

Randomized with seed 721296
----------------
COV    FILE                                        LINES RELEVANT   MISSED
 97.1% lib/mix/tasks/compile.unused.ex               189       34        1
100.0% lib/mix_unused/analyze.ex                      39       10        0
100.0% lib/mix_unused/analyzers/private.ex            29        6        0
100.0% lib/mix_unused/analyzers/unused.ex             18        3        0
100.0% lib/mix_unused/config.ex                       51        7        0
 90.0% lib/mix_unused/exports.ex                      91       20        2
 90.0% lib/mix_unused/filter.ex                      130       10        1
 92.9% lib/mix_unused/tracer.ex                       93       14        1
[TOTAL]  95.2%
----------------

[hauleth]

@marc0s if you want you can replace ExCoveralls with covertool (which is IMHO much simpler). This one works without any problems.