The Elixir equivalent of Rspec’s focus: true
10 December 2017
Rspec’s focus: true can be used to just run a subset of specs. To achieve something similar with Elixir, there are two main approaches that I have used.
Line number targeting
You can specify the test’s line number from the command line. Here’s an example:
$ mix test test/address_builder/au/import/gnaf_importer_test.exs:41
This will run just the test on line 41 of the file.
Targeting with tags
You can use tags to mark a test (or multiple tests) to be run. Here’s an example:
@tag :focus
test "with mixed case" do
assert StringUtil.titleize("weLLington") == "Wellington"
end
You can then run your test with the --only option:
$ mix test --only focus
It’s also compatible with the mix_test_watch package, so any edits will be retested straight away.
$ mix test.watch --only focus
Further reading
- Learn more from the official ExUnit configuration options.
- Learn more about skipping tests in this article by Pomodoro.