How do I mock a block argument in RSpec?

user_2923108 0
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Let's say I am calling a Ruby method with a block argument in ruby:

  Net::SFTP.start('testhost.com', 'test_user', keys: ['key']) do |sftp|
    sftp.upload!('/local', '/remote')
  end

How can I test that the upload! method was called with the correct arguments?

I could get this far, testing the arguments for #start,

  expect(Net::SFTP).
    to receive(:start) do |host, username, keyword_args, &block|
      expect(host).to eq("testhost.com")
      expect(username).to eq("test_user")
      expect(keyword_args).to eq(keys: ["test_key"])
    end

But I can't figure out how to test that #upload! was called in the block.

rspec-rails rspec ruby-on-rails ruby
1 Answers

Make use of and_yield - this works best when combined with allow().to receive and have_received matcher:

sftp = spy
allow(Net::SFTP).to receive(:start).and_yield(sftp)

# execute your code here

expect(Net::SFTP).to have_received(:start).with("testhost.com", "test_user", keys: ["test_key"])
expect(sftp).to have_received(:upload!).with('./local', '/remote')
user_23362310
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