WARNING: From function: testing
         on line 2 of /sass/spec/sass_3_5/warn-directive/functions-in-stack/input.scss, in `issues-warning'
         from line 7 of /sass/spec/sass_3_5/warn-directive/functions-in-stack/input.scss, in `calls-function-that-warns'
         from line 11 of /sass/spec/sass_3_5/warn-directive/functions-in-stack/input.scss
