Update Python demos with tests. (#5651)

* Remove GPU memory usage demo.
* Add tests for demos.
* Remove `silent`.
* Remove shebang as it's not portable.

demo/kaggle-higgs/higgs-cv.py

@@ -8,7 +8,7 @@ label  = train[:,32]
 data   = train[:,1:31]
 weight = train[:,31]
 dtrain = xgb.DMatrix( data, label=label, missing = -999.0, weight=weight )
-param = {'max_depth':6, 'eta':0.1, 'silent':1, 'objective':'binary:logitraw', 'nthread':4}
+param = {'max_depth':6, 'eta':0.1, 'objective':'binary:logitraw', 'nthread':4}
 num_round = 120
 
 print ('running cross validation, with preprocessing function')

demo/kaggle-higgs/higgs-numpy.py

@@ -37,7 +37,6 @@ param['scale_pos_weight'] = sum_wneg/sum_wpos
 param['eta'] = 0.1
 param['max_depth'] = 6
 param['eval_metric'] = 'auc'
-param['silent'] = 1
 param['nthread'] = 16
 
 # you can directly throw param in, though we want to watch multiple metrics here

demo/kaggle-higgs/higgs-pred.py

@@ -45,6 +45,3 @@ for k, v in res:
 fo.close()
 
 print ('finished writing into prediction file')
-
-
-

demo/kaggle-higgs/speedtest.py

@@ -36,7 +36,6 @@ param['scale_pos_weight'] = sum_wneg/sum_wpos
 param['bst:eta'] = 0.1
 param['bst:max_depth'] = 6
 param['eval_metric'] = 'auc'
-param['silent'] = 1
 param['nthread'] = 4
 
 plst = param.items()+[('eval_metric', 'ams@0.15')]