If you give no options to ExUnit runner, it sends an empty string as the pattern instead of just running mix test without any pattern

[thewoolleyman]

It's a bug that empty arguments aren't handled.

As a work-around, you could just make a fake flag, like --include not_a_tag.

See more details on this PR: #707 (comment)

[qd3v]

This work-around doesn't work for me either (v5.1.0), still empty quotes passed:

No file named

This does :)

defp deps do
  [{:mix_test_watch, "~> 0.3", only: :dev, runtime: false}]
end