Crystal function to capture stdin and stdout and redirect them within the block, returning an array containing 2 strings

with_std.cr

def with_std(&block)
    original_stdout = File.open("/dev/null")
    original_stdout.reopen(STDOUT)

    original_stderr = File.open("/dev/null")
    original_stderr.reopen(STDERR)

    stdout_reader, stdout_writer = IO.pipe
    stderr_reader, stderr_writer = IO.pipe

    STDERR.reopen(stderr_writer)
    STDOUT.reopen(stdout_writer)

    yield

    stdout_writer.close
    stderr_writer.close

    STDOUT.reopen(original_stdout)
    STDERR.reopen(original_stderr)

    return [stdout_reader.gets_to_end, stderr_reader.gets_to_end]
ensure
    [stdout_reader, stderr_reader].each(&.try(&.close))
    STDOUT.reopen(original_stdout.not_nil!)
    STDERR.reopen(original_stderr.not_nil!)
end