ExCoveralls

An elixir library that reports test coverage statistics, with the option to post to coveralls.io service. It uses Erlang's cover to generate coverage information, and posts the test coverage results to coveralls.io through the json API.

Currently, it's under trial for travis-ci integration.

• coverage_sample is a basic example project.
• excoveralls_umbrella is an example on umbrella project.

Settings

mix.exs

Add the following parameters.

• test_coverage: [tool: ExCoveralls] for using ExCoveralls for coverage reporting.
• preferred_cli_env: [coveralls: :test] for running mix coveralls in :test env by default
  • It's an optional setting for skipping MIX_ENV=test part when executing mix coveralls tasks.
• test_coverage: [test_task: "espec"] if you use Espec instead of default ExUnit.
• :excoveralls in the deps function.

def project do
  [ app: :excoveralls,
    version: "1.0.0",
    elixir: "~> 1.0.0",
    deps: deps(Mix.env),
    test_coverage: [tool: ExCoveralls],
    preferred_cli_env: ["coveralls": :test, "coveralls.detail": :test, "coveralls.post": :test],
    # if you want to use espec,
    # test_coverage: [tool: ExCoveralls, test_task: "espec"]
  ]
end

defp deps do
  [{:excoveralls, "~> 0.4", only: :test}]
end

Usage

Mix Tasks

• mix coveralls
• mix coveralls.travis
• mix coveralls.post
• mix coveralls.detail

[mix coveralls] Show coverage

Run the MIX_ENV=test mix coveralls command to show coverage information on localhost. This task locally prints out the coverage information. It doesn't submit the results to the server.

$ MIX_ENV=test mix coveralls
...
----------------
COV    FILE                                        LINES RELEVANT   MISSED
100.0% lib/excoveralls/general.ex                     28        4        0
 75.0% lib/excoveralls.ex                             54        8        2
 94.7% lib/excoveralls/stats.ex                       70       19        1
100.0% lib/excoveralls/poster.ex                      16        3        0
 95.5% lib/excoveralls/local.ex                       79       22        1
100.0% lib/excoveralls/travis.ex                      23        3        0
100.0% lib/mix/tasks.ex                               44        8        0
100.0% lib/excoveralls/cover.ex                       32        5        0
[TOTAL]  94.4%
----------------

Specifying the --help option displays the options list for available tasks.

Usage: mix coveralls
  Used to display coverage

  -h (--help)         Show helps for excoveralls mix tasks

  Common options across coveralls mix tasks

  -u (--umbrella)     Show overall coverage for umbrella project.
  -v (--verbose)      Show json string for posting.

Usage: mix coveralls.detail [--filter file-name-pattern]
  Used to display coverage with detail
  [--filter file-name-pattern] can be used to limit the files to be displayed in detail

Usage: mix coveralls.travis
  Used to post coverage from Travis CI server

Usage: mix coveralls.post [options] [coveralls-token]
  Used to post coverage from local server using token
  [coveralls-token] should be specified here or in COVERALLS_REPO_TOKEN
  environment variable

  -n (--name)         Service name ('VIA' column at coveralls page)
  -b (--branch)       Branch name ('BRANCH' column at coveralls page)
  -c (--committer)    Committer name ('COMMITTER' column at coveralls page)
  -m (--message)      Commit message ('COMMIT' column at coveralls page)
  -s (--sha)          Commit SHA (required when not using Travis) 

[mix coveralls.travis] Post coverage to travis

Specify mix coveralls.travis in the .travis.yml. This task is for submiting the result to the coveralls server when Travis-CI build is executed.

.travis.yml

language: erlang
otp_release:
  - R16B
before_install:
  - git clone https://github.com/elixir-lang/elixir
  - cd elixir && make && cd ..
before_script: "export PATH=`pwd`/elixir/bin:$PATH"
script:
  - "MIX_ENV=test mix do deps.get, compile, coveralls.travis"

[mix coveralls.post] Post coverage from localhost

Acquire the repository token of coveralls.io in advance, and run the mix coveralls.post command. It is for submitting the result to coveralls server from localhost.

The token can be specified as a mix task argument, or as an environment variable (COVERALLS_REPO_TOKEN).

$ MIX_ENV=test mix coveralls.post [YOUR_TOKEN]
...
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 16958  100    64  100 16894     23   6330  0:00:02  0:00:02 --:--:--  7644
{"message":"Job #xx.1","url":"https://coveralls.io/jobs/xxxx"}

[mix coveralls.detail] Show coverage with detail

This task displays coverage information at the source-code level with colored text. Green indicates a tested line, and red indicates lines which are not tested. When reviewing many source files, pipe the output to the less program (with the -R option for color) to paginate the results.

$ MIX_ENV=test mix coveralls.detail | less -R
...
----------------
COV    FILE                                        LINES RELEVANT   MISSED
100.0% lib/excoveralls/general.ex                     28        4        0
...
[TOTAL]  94.4%

--------lib/excoveralls.ex--------
defmodule ExCoveralls do
  @moduledoc """
  Provides the entry point for coverage calculation and output.
  This module method is called by Mix.Tasks.Test
...

Also, displayed source code can be filtered by specifying arguments (it will be matched against the FILE column value). The following example lists the source code only for general.ex.

$ MIX_ENV=test mix coveralls.detail --filter general.ex
...
----------------
COV    FILE                                        LINES RELEVANT   MISSED
100.0% lib/excoveralls/general.ex                     28        4        0
...
[TOTAL]  94.4%

--------lib/excoveralls.ex--------
defmodule ExCoveralls do
  @moduledoc """
  Provides the entry point for coverage calculation and output.
  This module method is called by Mix.Tasks.Test
...

coveralls.json

coveralls.json provides a setting for excoveralls.

The default coveralls.json file is stored in deps/excoveralls/lib/conf, and custom coveralls.json files can be placed in the mix project root. The custom definition is prioritized over the default one (if definitions in custom file are not found, then the definitions in the default file are used).

Stop Words

Stop words defined in coveralls.json will be excluded from the coverage calculation. Some kernal macros defined in Elixir are not considered "covered" by Erlang's cover library. It can be used for excluding these macros, or for any other reasons. The words are parsed as regular expression.

Coverage Options

• treat_no_relevant_lines_as_covered
  • By default, coverage for [files with no relevant lines] are displayed as 0% for aligning with coveralls.io behavior. But, if treat_no_relevant_lines_as_covered is set to true, it will be displayed as 100%.

{
  "default_stop_words": [
    "defmodule",
    "defrecord",
    "defimpl",
    "def.+(.+\/\/.+).+do"
  ],

  "custom_stop_words": [
  ],

  "coverage_options": {
    "treat_no_relevant_lines_as_covered": true
  }
}

Notes

• If mock library is used, it will show some warnings during execution.
  • eproxus/meck#17
• In case Erlang clashes at mix coveralls, executing mix test in advance might avoid the error.
• When erlang version 17.3 is used, an error message (MatchError) no match of right hand side value: "" can be shown. Refer to issue #14 for the details.
  • parroty#14

Todo

• It might not work well on projects which handle multiple project (Mix.Project) files.
  • Needs improvement on file-path handling.