Four failures in the main branch
self = <test_cli.CodeGeneratorTests testMethod=test_cli__<'fib', 'kotlin'>>, case = 'fib', lang = 'kotlin'
self = <test_cli.CodeGeneratorTests testMethod=test_cli__<'rect', 'kotlin'>>, case = 'rect', lang = 'kotlin'
self = <test_cli.CodeGeneratorTests testMethod=test_cli__<'print', 'kotlin'>>, case = 'print', lang = 'kotlin'
self = <test_cli.CodeGeneratorTests testMethod=test_cli__<'print', 'dart'>>, case = 'print', lang = 'dart'

The last one is caused by not being able to find the package `sprintf`. I'm not super familiar with how to install packages with dart.