Unit testing & Functional testing. Noob questions
Agis A.
Colin Law
> Hola!
>
> I'm new to Rails (it's my 2nd day reading the Agile development with Rails
> book) and I'm kinda confused with the tests.
>
> So let me get this straight: With unit testing, we see if our model is
> working as it should (as our app's specifications demands) and Rails
> provides us with all the unit testing features just to make our lifes
> easier, so we don't have to manually enter values to see if they're accepted
> or not. Is that right? And we're doing these tests to save ourself from
> future work for fixing bugs in our code etc. With unit testing we can
> pre-emptively fix our code's possible bugs, right from the beggining.
>
> Unit testing seems clear, but Functional testing is a little confusing to
> me: Why are we doing this? Where does it helps us? I know that we're testing
> for example if there are certain elements in our rendered views, for
> example: assert_select '#columns #side a', minimum: 4 but how could we
> *not* have these elements in our views?
It may seem obvious to you that the views are basically all right
because you can see that they are when you run the s/w. However,
perhaps there are a few conditions that change the details of what
appears on the page, maybe you view the page as a normal user and as
an admin, or perhaps with a different value of some field in the
database the view changes some detail. No problem, just try each of
these conditions and check it is ok. You can easily do this each time
you update the website.
Now add another 50 different pages ( a number of different controllers
and the different views for that controller). Each of those will have
a number of things you need to check you have not accidentally messed
up when you release a new version of the site. To manually check that
all the views still operate correctly becomes virtually impossible.
With automated testing you can be reasonably sure that you have not
accidentally messed something up and will allow you to sleep soundly
in your bed at night.
Colin
Agis A.
The unit testing of models that we did previously seemed straightforward
enough. We called a method and compared what it returned against what
we expected it to return. But now we are dealing with a server that processes
requests and a user viewing responses in a browser. What we will need is
functional tests that verify that the model, view, and controller work well
together. Never fear, Rails makes this easy too.
Colin Law
It is also checking that the controller is calling appropriate model
methods. That may be what it means. But mostly it is about controller
and views, yes. It is not only checking that the correct data appears
on the view, but also checking that the correct view is shown in the
first place.
Colin
Agis A.
Nopik
aiming
at testing system as a whole. I.e. unit testing do not check how
elements work
together.
Moreover, over the course of project code changes. So, new bugs are
introduced, too.
Things which seem impossible at the moment ('we always have these
elements in our views')
after code changes are not so impossible anymore ;) This is especially
true when new
coder joins the team and do not know previous assumptions.
> I'm new to Rails (it's my 2nd day reading the *Agile development with Rails
> *book) and I'm kinda confused with the tests.
>
> So let me get this straight: With* unit* testing, we see if our model is