Use cp_r in local backend with recursive option

[okuramasafumi]

When recursive optionfor upload! method is true, local argument is likely to be a String representing a directory, but FileUtils.cp doesn't accept it. So here we use FileUtils.cp_r instead.

[leehambley]

Thanks for the patch @okuramasafumi we'll need a test to verify this as working, and as you're working in this area, you may want to fix the build, which is currently failing because _options shouldn't be prefixed if it's now used in the function according to Rubocop.

[okuramasafumi]

@leehambley OK, I'll change variable name from _options to option. Also, I'll add tests for upload! method, which currently doesn't exist.

[okuramasafumi]

@leehambley Btw, do you have a plan for a test or stub backend? I used local backend for tests, but it feels like it lacks some features, such as stubbing executions.

[leehambley]

You ought to be able to use the stubbing from the test framework, it's a fairly simple unit test that the method was called, I don't think we need to test the standard library behaves correctly!

[okuramasafumi]

Sorry for the delay, I fixed the test so please check this again!

[mattbrictson]

Hi @okuramasafumi, thanks again for the PR! I don't see the test that you mentioned. Can you make sure all your changes have been pushed?

[okuramasafumi]

@mattbrictson I added tests and squashed commits.

[mattbrictson]

Excellent work! Thanks ✨