What goal do you have in mind for this test? From the examples you gave, it looks like you are only testing how RSpec’s verifying doubles work. For example, this expectation:
expect(html).to respond_to(:parse).with_keywords(:body, :headers) …isn’t exercising your code at all, because you’ve declared html as a test double, so it’s just testing how doubles work. If you’re trying to test the HTML class, you should not use a double in its place. Test doubles are intended for when you want to control the environment in which you test something, by replacing some collaborators with fake versions. They’re not intended to ever replace the thing you are testing—once you do that, you’re no longer testing the thing. Myron On Mon, Sep 18, 2017 at 11:03 PM, Steven Webb <[email protected]> wrote: > I'm having trouble testing a method signature change from taking a single > argument (a hash) to using keyword arguments. I've created a contrived > example of HTML parsing to simplify things (I'm not actually writing a html > parser): > > class HTML > def parse(body) # body is a hash > ... > end > end > > I want to update it so that it can take an optional headers argument. It > becomes: > > class HTML > def parse(body: , headers: {}) # body and headers are both hashes > end > end > > In a related unit test of a different class I'm using something like this: > > RSpec.describe "calling the parser" do > let(:html) { instance_double("HTML", parse: nil) } > let(:body) { double("body") } > let(:headers) { double("headers") } > > before { html.parse(body: body, headers: headers) } > > it "allows passing optional headers" do > expect(html).to have_received(:parse).with(body: body, headers: > headers) > end > end > > The problem I've got is that this test passes before updating the HTML > class. After updating the HTML class it correctly detects the keywords as > arguments and passes. Before it incorrectly determines the keywords are the > "body" hash and passes. Both are valid ruby, but the method signature has > changed (at least to me, possibly not to the VM). I tried: > > it "allows an optional headers argument" do > expect(html).to respond_to(:parse).with_keywords(:body, :headers) > end > > but that fails (presumably the instance double is using method_missing). > > 1) calling the parser allows an optional headers argument > Failure/Error: expect(html).to respond_to(:parse).with_keywords(:body, > :headers) > expected #<InstanceDouble(HTML) (anonymous)> to respond to :parse > with keywords :body and :headers > # ./spec/keyword_args_spec.rb:40:in `block (2 levels) in <top > (required)>' > > Can anyone explain how I should be testing this correctly? > > Thanks > > Steve. > > -- > You received this message because you are subscribed to the Google Groups > "rspec" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > To view this discussion on the web visit https://groups.google.com/d/ > msgid/rspec/8dbe9153-45c0-44f7-a0be-e6fa6ceffd7e%40googlegroups.com > <https://groups.google.com/d/msgid/rspec/8dbe9153-45c0-44f7-a0be-e6fa6ceffd7e%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "rspec" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/rspec/CADUxQmsXyKTx%3DRDk0pnZksU3VZtk79Sf4jg-PBAG-55qPxRJkA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
