Terminal colors running test-unit in Rails

I can't seem to make colors work when running test unit in rails. I have tried so far:

• $ bundle exec bin/rake test TESTOPTS="--use-color" -> It tells me that --use-color is an invalid option.

• I made a file called test-unit.yml with:

  runner: console
  console_options:
    arguments: --use-color=yes
  
  

still nothing.

• Following the docs (http://ift.tt/1RNjSOc) I added:

  runner: console
  console_options:
    color_scheme: personal
  color_schemes:
    personal:
      success:
        name: green
        bold: true
      failure:
        name: red
        bold: true
  
  

Still nothing!

Do I need anything else?

Ruby version: 2.3.0p0 (2015-12-25 revision 53290) [x86_64-linux]

Rails version: Rails 4.2.6