Method: Minitest::Assertions#assert_output

Defined in:
lib/minitest/assertions.rb

#assert_output(stdout = nil, stderr = nil) ⇒ Object

Fails if stdout or stderr do not output the expected results. Pass in nil if you don't care about that streams output. Pass in “” if you require it to be silent. Pass in a regexp if you want to pattern match.

assert_output(/hey/) { method_with_output }

NOTE: this uses #capture_io, not #capture_subprocess_io.

See also: #assert_silent


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# File 'lib/minitest/assertions.rb', line 329

def assert_output stdout = nil, stderr = nil
  flunk "assert_output requires a block to capture output." unless
    block_given?

  out, err = capture_io do
    yield
  end

  err_msg = Regexp === stderr ? :assert_match : :assert_equal if stderr
  out_msg = Regexp === stdout ? :assert_match : :assert_equal if stdout

  y = send err_msg, stderr, err, "In stderr" if err_msg
  x = send out_msg, stdout, out, "In stdout" if out_msg

  (!stdout || x) && (!stderr || y)
rescue Assertion
  raise
rescue => e
  raise UnexpectedError, e
end