Method: Minitest::Assertions#assert_raises

Defined in:
lib/minitest/assertions.rb

#assert_raises(*exp) ⇒ Object

Fails unless the block raises one of exp. Returns the exception matched so you can check the message, attributes, etc.

exp takes an optional message on the end to help explain failures and defaults to StandardError if no exception class is passed. Eg:

assert_raises(CustomError) { method_with_custom_error }

With custom error message:

assert_raises(CustomError, 'This should have raised CustomError') { method_with_custom_error }

Using the returned object:

error = assert_raises(CustomError) do
  raise CustomError, 'This is really bad'
end

assert_equal 'This is really bad', error.message



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# File 'lib/minitest/assertions.rb', line 424

def assert_raises *exp
  flunk "assert_raises requires a block to capture errors." unless
    block_given?

  msg = "#{exp.pop}.\n" if String === exp.last
  exp << StandardError if exp.empty?

  begin
    yield
  rescue *exp => e
    pass # count assertion
    return e
  rescue Minitest::Assertion # incl Skip & UnexpectedError
    # don't count assertion
    raise
  rescue SignalException, SystemExit
    raise
  rescue Exception => e
    flunk proc {
      exception_details(e, "#{msg}#{mu_pp(exp)} exception expected, not")
    }
  end

  exp = exp.first if exp.size == 1

  flunk "#{msg}#{mu_pp(exp)} expected but nothing was raised."
end