@wojsmol The tests fail because your check (whether the function theme_setup exists) is wrong.
The parent theme you've picked is built using objects, not using procedural code. So your check needs to look for a class or method, not a function. Use something like the following:

// For stargazer parent theme:
wp eval 'var_export( class_exists( "Stargazer_Theme" ) );'
// For buntu child theme:
wp eval 'var_export( function_exists( "buntu_theme_setup" ) );'

should be fixed now - thanks

Thanks for your continued effort on this, @wojsmol !