Method: MiniTest::Assertions#capture_io

Defined in:
lib/minitest/unit.rb

#capture_io ⇒ Object

Captures $stdout and $stderr into strings:

out, err = capture_io do
  warn "You did a bad thing"
end

assert_match %r%bad%, err


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# File 'lib/minitest/unit.rb', line 323

def capture_io
  require 'stringio'

  orig_stdout, orig_stderr         = $stdout, $stderr
  captured_stdout, captured_stderr = StringIO.new, StringIO.new
  $stdout, $stderr                 = captured_stdout, captured_stderr

  yield

  return captured_stdout.string, captured_stderr.string
ensure
  $stdout = orig_stdout
  $stderr = orig_stderr
end