method

capture_subprocess_io

v2_1_10 - Show latest stable - 0 notes - Class: Assertions

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What's this?

capture_subprocess_io() public

Captures $stdout and $stderr into strings, using Tempfile to ensure that subprocess IO is captured as well.

out, err = capture_subprocess_io do
  system "echo Some info"
  system "echo You did a bad thing 1>&2"
end

assert_match %r%info%, out
assert_match %r%bad%, err

NOTE: This method is approximately 10x slower than #capture_io so only use it when you need to test the output of a subprocess.

Show source

# File lib/minitest/unit.rb, line 503
    def capture_subprocess_io
      require 'tempfile'

      captured_stdout, captured_stderr = Tempfile.new("out"), Tempfile.new("err")

      synchronize do
        orig_stdout, orig_stderr = $stdout.dup, $stderr.dup
        $stdout.reopen captured_stdout
        $stderr.reopen captured_stderr

        begin
          yield

          $stdout.rewind
          $stderr.rewind

          [captured_stdout.read, captured_stderr.read]
        ensure
          captured_stdout.unlink
          captured_stderr.unlink
          $stdout.reopen orig_stdout
          $stderr.reopen orig_stderr
        end
      end
    end

capture_subprocess_io

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