Re: [stellation-res] Unit test organization

[Jeffrey Howard <jhoward@xxxxxxxxxxxxxxx>]

Hello,

> Eclipse provides good support for this metaphor since it permits multiple
> source tree  within a single project. So all we need to do is to create a
> parallel structure to the "src" rooted structure that currently exists that
> will hold the additional low level unit tests. We use this principle with
> great success in my organization whre we name the parallel tree "test".
> 
> Any thoughts on this?

There is another way of organizing tests that we use here at work.  It
takes advantage of the fact that inner classes can still extend other
classes.  The setup looks like:

class MyClass {
	private Object privateData;
	Object packageData;
	public Object publicData;

	private Object privateMethod() {
		...
	}

	Object packageMethod() {
		...
	}

	public Object publicMethod() {
		...
	}

	public static class TestMyClass extends TestCase {
		... [Lots of JUnit tests]...
	}
}

The advantage of doing it this way is that TestMyClass gets access to
everything inside the class that it's testing, including private data
and methods such as privateData and privateMethod in the example
above.  Since we do a fair amount of white box testing as part of our
unit testing, the added visibility to the test class is often quite
helpful.  It saves us a lot of effort in reconstructing what the
internal state of the object must be from external behavior.  Another
advantage is that it's very easy on the build system, because the tool
set doesn't need to be able to handle multiple source trees.  Though
as you pointed out, this isn't really a problem if you're developing
under Eclipse.  When building up the test suite, you just use a call
of the form:

ts.addTestSuite( MyClass.TestMyClass.class );

Eclipse hasn't had any trouble automatically detecting these when
doing a Run as JUnit command.

The corresponding disadvantage is that it's no longer possible to ship
a release without having the unit tests go with it.  Personally,
that's never bothered me.  I suppose if you're distributing by
download over very slow links, it could become a problem.

Stylistically, some people like the fact that the class and the tests
for it are all rolled up into one file.  Some people find that having
the unit tests appended to the source file makes the source file seem
cluttered.  I like having everything together in one place.  Eclipse's
JDT makes it easy enough to navigate source files that I don't find
that it impedes my ability to work with the code.  That seems to be
mostly a matter of personal preference, though.


Jeffrey