Fix failure file dump when output has invalid UTF8

[skipkayhil]

Previously, any invalid UTF-8 in test output would prevent the entire JSON failure file from being dumped, because the Ruby JSON library validates that its output is UTF-8.

This commit aims to fix this issue by encoding the output as UTF-8 before it gets to JSON so that the file can always be dumped.

[ChrisBr]

Makes sense, thanks!

[ChrisBr]

Are the failed tests for 2.7 related?

Minitest::UnexpectedError:         FrozenError: can't modify frozen String: "\e[31mFAIL\e[0m Minitest::Test#a\n\e[33mSomething went wrong\e[0m\n    test/support/reporter_test_helper.rb:15:in `runnable'\n    test/support/reporter_test_helper.rb:6:in `result'\n    test/minitest/reporters/junit_reporter_test.rb:65:in `test_generate_junitxml_for_errored_test'\n\n"

[hmcguire-shopify]

Are the failed tests for 2.7 related?

Minitest::UnexpectedError:         FrozenError: can't modify frozen String: "\e[31mFAIL\e[0m Minitest::Test#a\n\e[33mSomething went wrong\e[0m\n    test/support/reporter_test_helper.rb:15:in `runnable'\n    test/support/reporter_test_helper.rb:6:in `result'\n    test/minitest/reporters/junit_reporter_test.rb:65:in `test_generate_junitxml_for_errored_test'\n\n"

Oh, whoops I didn't see those with all the python failures 😅 I'll get those fixed

[hmcguire-shopify]

Okay, should be good now 🟢

TIL encode! works on frozen strings only in Ruby 3.0+

[ChrisBr]

Thanks for fixing!