Returns the list of AbstractTargets which are used as sources.
            The extra properties specified for sources are not represented.
            The only used of this rule at the moment is the '--dump-tests'
            feature of the test system.

def sources (self):
        """ Returns the list of AbstractTargets which are used as sources.
            The extra properties specified for sources are not represented.
            The only used of this rule at the moment is the '--dump-tests'
            feature of the test system.
        """
        if self.source_targets_ == None:
            self.source_targets_ = []
            for s in self.sources_:
                self.source_targets_.append(resolve_reference(s, self.project_)[0])

        return self.source_targets_