From: Phlip <phlipcpp@...>
Date: 2006-09-07T10:05:21+09:00
Subject: Abstract Tests vs AutoRunner

Rubies:

I'm trying to get some elaborate test suites working via the hidden call to 
AutoRunner.

Because I can't declare which suites to run, the system tests anything that 
derives from TestCase.

I want to do this:

class AbstractSuite < Test::Unit::TestCase
    def test_foo()
        p derive()
    end
end

class ConcreteSuiteA < AbstractSuite
    def derive()
        return 'like this'
    end
end

class ConcreteSuiteB < AbstractSuite
    def derive()
        return 'like that'
    end
end

That's the skeleton of the Abstract Test pattern, which is a major Good 
Thing. It prevents us from writing zillions of duplicate test cases with 
minimal differences between each one. For example, my derive() could return 
an object that must pass the same tests as another object, obeying Liskov 
Substitution Principle.

However, I can't do it like that, because AutoRunner hoovers up every class 
derived from TestCase, and runs all of them as suites. I predictably get 
"test_foo(AbstractSuite): NoMethodError: undefined method `derive'"

The ugly fix is this:

class ConcreteSuiteA < Test::Unit::TestCase
    def test_foo()
        p derive()
    end

    def derive()
        return 'like this'
    end
end

class ConcreteSuiteB < ConcreteSuiteA
    def derive()
        return 'like that'
    end
end

That works, but it's "not OO". ConcreteSuiteB is not truly a derived version 
of ConcreteSuiteA.

So I'm asking this question because I don't understand mixins, or 
AutoRunner, enough to fix this.

Could a mixin grant test cases to two concrete classes? Alternately, does 
AutoRunner have a feature to bump a suite from its list?

-- 
  Phlip
  http://c2.com/cgi/wiki?ZeekLand <-- NOT a blog!!!