如何在 RSPEC 中测试链调用？

Question

I have call looks like

1) foo1 => MyModel.where(id: my_model_ids)
2) foo2 => MyModel.where('date > :new_date', {new_date: DateTime.new(0)})
3) foo2.sum(:count)

How can I test this call Chain ? I tried this

where_mock = instance_double(ActiveRecord::Relation)
result_mock = instance_double(ActiveRecord::Relation)

filter = 'date > :new_date'
new_data_hash = {new_date: DateTime.new(0)}


expect(where_mock).to receive(:where).with(filter, new_data_hash).and_return(result_mock)
expect(result_mock).to receive(:sum)

But it didn't work

Answer 1

I think you're looking for receive_message_chain , https://relishapp.com/rspec/rspec-mocks/docs/working-with-legacy-code/message-chains

The example they give is:

allow(Article).to receive_message_chain("recent.published") { [Article.new] }

It's worth noting that use of this method is often symptomatic of a code smell.

If here you're testing that a message is received rather than the output, you can test the first method call in isolation, stub the result, and then test that the stub receives the second method call.