# Rspec questions: same file? mocks objects as params? **URL:** \ **Category:** Ruby\ **Created:** [November 14, 2007, 8:02pm UTC](https://www.ruby-forum.com/t/rspec-questions-same-file-mocks-objects-as-params/120209 "2007-11-14T20:02:41Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![dawillis](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/ebca7d/32.png) [@dawillis](https://www.ruby-forum.com/u/dawillis)\ **Post date:** [November 14, 2007, 8:02pm UTC](https://www.ruby-forum.com/t/rspec-questions-same-file-mocks-objects-as-params/120209/1 "2007-11-14T20:02:41Z")
I’m just getting started with rspec. Two questions: 1. Should the rspec be in the same file as the production code? The examples on the rspec site seem to indicate they should be in a separate file but I wanted to double check. 2. If I use mocks, am I supposed to pass them as parameters to my production code? If my code looked like: def read() db = database.instance() db.execute(…) end and I want to do a mock database connection do I have to write the production code like: def read(db=database.instance()) db.execute(…) end and then call it with read(my\_mock) ? ---
**Author:** ![dawillis](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/ebca7d/32.png) [@dawillis](https://www.ruby-forum.com/u/dawillis)\ **Post date:** [November 14, 2007, 8:33pm UTC](https://www.ruby-forum.com/t/rspec-questions-same-file-mocks-objects-as-params/120209/2 "2007-11-14T20:33:03Z")
On Nov 14, 2007 11:02 AM, David W. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > I’m just getting started with rspec. Two questions: > > 1. Should the rspec be in the same file as the production code? The > examples on the rspec site seem to indicate they should be in a separate > file but I wanted to double check. Specs should be separate. In a Rails app there’s a spec dir that parallels your app dir. If you’re writing a Ruby app from scratch then you’ll need to create it yourself. But definitely stick specs in separate files from production code. > and I want to do a mock database connection do I have to write the > production code like: > > def read(db=database.instance()) > db.execute(…) > end > > and then call it with read(my\_mock) ? You can do it that way, or you can stub the call to #instance and have it return the mock. Also, without knowing anything about your code 🙂 I would be more likely to pass the datastore into the constructor: class Person def initialize(datastore) @datastore = datastore end def read conn = @datastore.instance conn.execute(…) end end Then your spec would look something like: describe Person, " reading a record" do before(:each) do @mock\_connection = mock(“db connection”) @mock\_pool = stub(“connection pool”, :instance =\> @mock\_connection) ``` @person = Person.new @mock_pool ``` end it “should get a connection” do @mock\_pool.should\_receive(:instance).and\_return @mock\_connection @person.read end it “should select data from the database” do @mock\_connection.should\_receive(:execute).with(…) @person.read end end Which is sort of ugly because you have a mock returning a mock, but such is life with a singleton 🙂 Pat ---
**Author:** ![dawillis](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/ebca7d/32.png) [@dawillis](https://www.ruby-forum.com/u/dawillis)\ **Post date:** [November 15, 2007, 3:09am UTC](https://www.ruby-forum.com/t/rspec-questions-same-file-mocks-objects-as-params/120209/3 "2007-11-15T03:09:11Z")
> 1. If I use mocks, am I supposed to pass them as parameters to my > production code? If I understand correctly you shouldn’t change your production code at all. The goal of mocks, basically, is that they enable you to cleanly separate the specs from the production code. With the example stuff Pat wrote, you get that. You want to set up the mocks to parallel whatever is happening in the production code that you don’t actually want run by the specs - hitting the database is part of that because the DB gives you a bottleneck and speed really matters when it comes to tests (you’ll only actually use the tests (or specs) if they’re fast). But the point is you shouldn’t change production code to do anything with a mock. The whole point of a mock is that it allows your tests or specs to run as if the production code was behaving as normal. – Giles B. Podcast: [http://hollywoodgrit.blogspot.com](http://hollywoodgrit.blogspot.com) Blog: [http://gilesbowkett.blogspot.com](http://gilesbowkett.blogspot.com) Portfolio: [http://www.gilesgoatboy.org](http://www.gilesgoatboy.org) Tumblelog: [http://giles.tumblr.com](http://giles.tumblr.com) ---
**Author:** ![dawillis](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/ebca7d/32.png) [@dawillis](https://www.ruby-forum.com/u/dawillis)\ **Post date:** [November 15, 2007, 3:19am UTC](https://www.ruby-forum.com/t/rspec-questions-same-file-mocks-objects-as-params/120209/4 "2007-11-15T03:19:42Z")
On Nov 14, 2007 6:08 PM, Giles B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > 1. If I use mocks, am I supposed to pass them as parameters to my > > production code? > > If I understand correctly you shouldn’t change your production code at all. Well, not quite. If you’re retrofitting tests onto existing code, you’ll often need to change the production code to work with mocks. That’s because most code that isn’t written with testability in mind tends to be too coupled, because it’s just easier to write code that way. So you certainly could have to break those dependencies when you’re writing tests after the fact. But you’re right, the whole point of mocks is to allow you to swap in a different object with the same interface. Mocking isn’t a silver bullet of course…code that’s easy to mock isn’t necessarily well-design, but in general there are fewer dependencies - a Good Thing. Pat