lcov_ex

Test coverage module to generate a lcov.info file for an Elixir project.

The docs can be found at https://hexdocs.pm/lcov_ex.

Why

Many test coverage tools use lcov files as an input to generate reports.

You can use it as I do to watch inline coverage progress with the following editors:

• VSCode, using the Coverage Gutters extension.
• Atom, using the lcov-info extension (it requires you to change the output folder to "coverage", see below).

Please let me know if you made it work in your previously unlisted favorite editor. Or, if you're really nice, just add it to this list yourself :slightly_smiling_face:

Installation

Add to your dependencies:

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

Then, select LcovEx as your test coverage tool in your project configuration:

def project do
  [
    ...
    test_coverage: [tool: LcovEx, output: "cover"],
    ...
  ]

The output option indicates the output folder for the generated file.

Optionally, the ignore_paths option can be a list of prefixes to ignore when generating the coverage report.

test_coverage: [tool: LcovEx, output: "cover", ignore_paths: ["test/"]],

Usage

Run tests with coverage:

mix test --cover

File should be created at ./cover/lcov.info by default.

TODOs

• Add missing FN lines, for the sake of completion.
• Make it work as a Task to avoid overwriting the test_coverage tool config.