Elixir's ExUnit supports all kinds of tags for customizing the behavior of your test suite. The :skip tag signals that ExUnit should skip over that specific test.

@tag :skip
test "this is a test that should not run" do
  assert false
end

When you run mix test, it will make sure to not execute any tests with the :skip tag.

Using the :skip tag can be a great temporary measure in a lot of situations. It is not a good long-term practice to keep these around and check them in.