Add missing unit test for PCA
Add missing unit test for PCA

kcompher/thunder,pearsonlab/thunder,mikarubi/thunder,zhwa/thunder,j-friedrich/thunder,oliverhuangchao/thunder,j-friedrich/thunder,oliverhuangchao/thunder,zhwa/thunder,thunder-project/thunder,kunallillaney/thunder,jwittenbach/thunder,mikarubi/thunder,broxtronix/thunder,poolio/thunder,poolio/thunder,pearsonlab/thunder,kcompher/thunder,broxtronix/thunder,kunallillaney/thunder