Newbie: how to preserve NoMethodError under stubbing?

Testing RSpec
1

Hi,

I’ve been browsing the RSpec book and the RDoc, but I can’t see how to
ensure the following:

Stub an instance with a method it doesn’t have and raise NoMethodError
(or something like it.)

I want to do this because I don’t want to use incorrect names for my
dependency methods…

Thanks,

Lille

2

On Fri, Jul 23, 2010 at 6:46 PM, Lille [email protected] wrote:

Hi,

I’ve been browsing the RSpec book and the RDoc, but I can’t see how to
ensure the following:

Stub an instance with a method it doesn’t have and raise NoMethodError
(or something like it.)

RSpec doesn’t support anything like that. I’m not sure if any of the
Ruby frameworks do, though I’ve been involved with conversations about
this sort of thing before.

I wouldn’t want behaviour like this myself unless it could be invoked
explicitly with a command line argument, but was otherwise off. In
other words, you could do something like:

rspec spec --audit-stubbed-methods

And then that would generate some sort of report.

Feel free to submit a feature request to
GitHub - rspec/rspec-mocks: RSpec's 'test double' framework, with support for stubbing and mocking if you’re interested in pursuing
such.

Cheers,
David

3

El 24/07/2010, a las 08:26, David C.
escribió:

Ruby frameworks do, though I’ve been involved with conversations about
this sort of thing before.

I’m not sure if I understand the request, but with RR you can do this:

require ‘rr’
=> true

extend RR::Adapters::RRMethods
=> main

foo = Object.new
=> #Object:0x101664bd8

stub(foo).bar { raise NoMethodError }
=> #RR::DoubleDefinitions::DoubleDefinition:0x10165ce60

foo.bar
NoMethodError: NoMethodError

Although like I said, not sure if I understood Lille’s request.

Cheers,
Wincent

4

Lille,

On Sat, 24 Jul 2010 01:26 -0500, “David C.”
[email protected] wrote:

Ruby frameworks do, though I’ve been involved with conversations about
Feel free to submit a feature request to
GitHub - rspec/rspec-mocks: RSpec's 'test double' framework, with support for stubbing and mocking if you’re interested in pursuing
such.

Cheers,
David

Most people ask for this kind of feature from their unit tests because
they’re not combining mocking unit tests with end-to-end acceptance
tests. Are you using both?

5

David,

Yes, your reading of the request is what I originally meant.

I appreciate the points made by others in this thread and the thread
David has referred to.

As I continue to learn RSpec I will undoubtedly avail myself of the
approaches recommended above or in the linked thread, but I think an
argument to stub() per the following could be useful:

f.stub(:barr, :throw_no_such_method_error=>true)
#=> Error: “The Foo class does not have a ‘barr’ method. Perhaps you
meant to stub ‘bar’”

Thanks,

Lille

6

On Jul 24, 2010, at 4:35 AM, Wincent C. wrote:

RSpec doesn’t support anything like that. I’m not sure if any of the
=> #Object:0x101664bd8

stub(foo).bar { raise NoMethodError }
=> #RR::DoubleDefinitions::DoubleDefinition:0x10165ce60
foo.bar
NoMethodError: NoMethodError

Although like I said, not sure if I understood Lille’s request.

I read the request as this:

class Foo
def bar; end
end

f = Foo.new
f.stub(:barr)
#=> Error: “The Foo class does not have a ‘barr’ method. Perhaps you
meant to stub ‘bar’”

For me this would have very limited utility because 1/2 the time I’m
deliberately stubbing methods that don’t even exist yet on doubles
doubling for objects that don’t even exist yet, which is why I wouldn’t
want it to be something that happens implicitly by default.

Here’s another thread on the same matter from a little over a year ago:

http://groups.google.com/group/rspec/browse_thread/thread/cf0b3eae192b9d8c/f5b77b008de628c7?lnk=gst&q=mock+audit#f5b77b008de628c7

Cheers,
David

7

On 24 Jul 2010, at 2:52 PM, Wincent C. wrote:

How about this:

f.stub.existing(:bar)

That’s probably RR influencing me there, which employs things like “stub.proxy” and so on. So maybe not such a good idea for rspec-mocks.

Another option might be to deprecate #stub! as an alias for #stub and
then bring it back as an equivalent to stub.existing above.

Ash

–
http://www.patchspace.co.uk/
http://www.linkedin.com/in/ashleymoran

8

El 24/07/2010, a las 15:34, Lille
escribió:

f.stub(:barr, :throw_no_such_method_error=>true)
#=> Error: “The Foo class does not have a ‘barr’ method. Perhaps you
meant to stub ‘bar’”

How about this:

f.stub.existing(:bar)

That’s probably RR influencing me there, which employs things like
“stub.proxy” and so on. So maybe not such a good idea for rspec-mocks.

Cheers,
Wincent