I can't test like I'm supposed to

So, I'm toward the end of converting my certificate handling in Puppet to using my nifty new indirection features, which will handle both reading and writing certs to disk and to remote servers (for signing). Yee-haw. The only bit left (I hope) is the certificate authority itself.

In the course of this work, I've created a 'SSL::Host' class that is basically a composite of a key, a certificate request, and a certificate, so it makes sense to treat a CA as a special case of that: It's various files are stored in different places, and it can sign certificates, but it's otherwise the same.

So, I need this class to read and write to different locations (easy, although not yet tested). I also want the CA to initialize itself completely upon creation -- that is, when I call CertificateAuthority.new, I want it to create and write to disk all of the files it needs. I think this is reasonable, because I don't think it's reasonable to either require the caller to call a setup method of some kind, nor is it reasonable to do it late-binding, since initialization failures would show up during a call to sign which is stupid.

Okay. Seems easy. Here's the kicker: I want to test that the CA always chooses its name as the value of the certname Puppet setting. It's pretty easy to write that basic test:

it "should always set its name to the value of :certname" do
    Puppet.settings.expects(:value).with(:certname).returns("whatever")
    Puppet::SSL::CertificateAuthority.new.name.should == "whatever"
end

Except... all that initialization stuff is happening (by design). So now I'm in the position of using this kind of hack:

Puppet::SSL::CertificateAuthority.any_instance.stubs(:setup_ca)

Which is mostly a hack just because that method is private -- you never need to call it, yet here we need to know it exists just for testing.

The only other option is literally about 15 lines of stubs, since the CA uses a bunch of other settings, which now all need to be stubbed because of my initial expectation, plus needing to stub out any file reading or writing.

I keep thinking that I'm just crazy, at some point I'll see the light and be able to write single-expectation tests with no setup code like Jay Fields recommends, but in reality, I think Jay is crazy. I can't fight that feeling, and I less and less want to.

Wed, 12 Mar 2008 | Tags: ruby, development, testing, mocks