Test behavior, not methods.

[Justin Martin]

Tomek,

I read your chapter about testing behavior, not methods (the example on the site).  I have been doing some javascript development as of late and I have been frequently testing the methods one by one.  However, the way I isolate the tests is by mocking out the other methods that are called by the method that I'm testing.  Is this a practical way to test?

Thanks,

Jusitn

[Tomek Kaczanowski]

Hi Justin,

I'm really not a JavaScript programmer so I'm not sure whether what I
have to say makes any sense. :)

When using object oriented approach, you should be worrying about your
classes/objects which should provide some interesting functionality.
This is also reflected by tests, which should do the same: do not
concentrate on the single method(s) but on a single functionality
provided by class. It very often happens that a single functionality =
single method, thus the popular approach of testing single method
works fine in many cases (but not in all of them).

Do you mean you are mocking out the methods of the same object that
you test? If so, then I have doubts if this is the right approach.
Usually you should care about the class under test (SUT) as a whole
and mock only what is outside (its collaborators). If you need to mock
methods of the SUT, it might mean that your objects is too complicated
(and maybe should be split into few objects with less functionality).
This is the answer I would give in the Java world, but I'm not sure
how it relates to your JavaScript development (i.e. JavaScript allows
you to be less object oriented than Java and still live happily).

--
Regards / Pozdrawiam
Tomek Kaczanowski
http://practicalunittesting.com