如果我正在测试rspec扩展，如何抑制在测试中失败的测试结果？

Question

I'm trying to write specs for an extension to rspec.

This is the gist of what I'm trying to test:

require 'rspec-let-and-after-extension'

RSpec.describe "let(...).and_after" do
  it 'is called if the `let` is invoked even if the example fails' do
    call_order = []

    RSpec.describe do
      let(:foo) { }.and_after { call_order << :and_after }
      it { foo; call_order << :example; raise 'failed!' }
    end.run

    expect(call_order).to eq [:example, :and_after]
  end
end

One of the important behaviours is that if running the example fails, the cleanup code still runs. So I test this by recording the order of the calls and raising an exception from the example.

Problem is, when I run it, it sees this block as a second example, which then fails with errors:

.F

Failures:

  1)  
     Got 0 failures and 2 other errors:

     1.1) Failure/Error: it { foo; call_order << :example; raise 'failed!' }
          RuntimeError:
            failed!
          # ./spec/spec.rb:43:in `block (4 levels) in <top (required)>'
          # ./spec/spec.rb:44:in `block (2 levels) in <top (required)>'

     1.2) Failure/Error: it { foo; call_order << :example; raise 'failed!' }
          RuntimeError:
            failed!
          # ./spec/spec.rb:43:in `block (4 levels) in <top (required)>'

Finished in 0.00167 seconds (files took 0.08011 seconds to load)
2 examples, 1 failure

Failed examples:

rspec ./spec/spec.rb:43 #  

As you can see, the output did have one dot, so the actual example passed . But then there is an F, because it has seen the internal example, run that, and unsurprisingly that one failed.

How do I make rspec not see this nested example as one of the examples it's supposed to run, so that this example completes with a single dot?

(If you're wondering about what the rspec devs themselves do about their tests, it looks like they use cucumber. Do they use cucumber because they couldn't figure this out either? :))

Answer 1

You can use the new sandboxing API (available in 3.2+).

RSpec.configure do |rspec|
  rspec.around do |ex|
    RSpec::Core::Sandbox.sandboxed do |config|
      # re-configure any configuration defined by your extension here
      # before allowing the example to run. The sandbox runs with a fresh
      # config instance, which means any configuration you have set in
      # `rspec-let-and-after-extension` will not apply while the example
      # is running.
      # config.extend MyExtensionModule
      ex.run
    end
  end
end