add unittest for dataset;test=develop

Author: danleifeng

python/paddle/fluid/tests/unittests/test_communicator_ps_gpu.py

@@ -74,7 +74,7 @@ def test_communicator_ps_gpu(self):
             batch_size=32, thread_num=1, pipe_command="cat", use_var=slots_vars)
         dataset.set_filelist(["test_communicator_ps_gpu.txt"])
         dataset._set_use_ps_gpu(1)
-        dataset.load_into_memory()
+        dataset.load_into_memory(is_shuffle=True)
 
         os.environ["TEST_MODE"] = "1"
         exe = fluid.Executor(fluid.CPUPlace())