improved and extended some tests

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/sampleselection@1559 d36ae590-6c38-44c5-9ba5-7217e93607d8
removed an obsolete test with a newly generated data set; the two following tests now use the originally generated data set (not the data set that belonged to the obsolete test) and hence, give different results

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/sampleselection@1560 d36ae590-6c38-44c5-9ba5-7217e93607d8