RSpec starts_with matcher variant using regular expressions

问题

Is there a variant of the RSpec start_with matcher that will use regular expression matching instead of equality when examining arrays of strings? (I don't mind writing my own; but I don't want to re-invent the wheel.)

Specifically, I want to have a spec that looks like this:

it 'begins with the standard header' do
  output = method_under_test
  # output is an array of Strings
  expect(output).to start_with([/foo/, /bar/])
end

This spec should pass if output[0] matches /foo/ and output[1] matches /bar/.

Assuming I do need to write my own matcher, is there a way to "overload" start_with, or do I need to choose a different name?

回答1:

It turns out that the solution is to use a combination of composing matchers and aliases:

it 'begins with the standard header' do
  output = method_under_test
  # output is an array of Strings
  expect(output).to start_with(
                a_string_matching(/foo/),
                a_string_matching(/bar/)
             )
end

来源：https://stackoverflow.com/questions/39254886/rspec-starts-with-matcher-variant-using-regular-expressions