add test

python/paddle/v2/framework/tests/test_nccl_ops.py

+import unittest, os
+import numpy as np
+import paddle.v2 as paddle
+from paddle.v2.framework.op import Operator
+import paddle.v2.framework.core as core
+from op_test import OpTest, create_op
+
+gpu_list = os.environ["NV_LIST"]
+
+if not core.is_compile_gpu() or not gpu_list:
+    exit(0)
+
+
+class TestNCCLAllReduce(unittest.TestCase):
+    def __init__(self):
+        self.op_type = "nnclAllReduce"
+        self.scope = core.Scope()