Hello,
I noticed a strange behaviour of dune runtest.
Say I have the following file test_colors.ml :

let f s =
  output_string stdout ( "\027[34m" ^ s ^ "\027[39m"); flush stdout
    in

    for i= 1 to 20 do
      f (string_of_int i)
    done

And the dune file

(test
 (name test_colors) )

When executing dune runtest, i get the following :

where I would have expected all the characters to be colorized instead.

I have (quickly) tested with different versions of dune; I think the problem appeared in version 1.11.0