Add unittests to check channelwise add

Author: JiayiFeng

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

@@ -252,5 +252,25 @@ def init_axis(self):
         self.axis = 1
 
 
+class TestElementwiseAddOp_channelwise_add(TestElementwiseAddOp):
+    def init_input_output(self):
+        self.x = np.random.rand(3, 20, 20).astype(self.dtype)
+        self.y = np.random.rand(3, 1, 1).astype(self.dtype)
+        self.out = self.x + self.y
+
+    def init_axis(self):
+        self.axis = -1
+
+
+class TestFP16ElementwiseAddOp_channelwise_add(TestFP16ElementwiseAddOp):
+    def init_input_output(self):
+        self.x = np.random.rand(3, 10, 20).astype(self.dtype)
+        self.y = np.random.rand(3, 1, 1).astype(self.dtype)
+        self.out = self.x + self.y
+
+    def init_axis(self):
+        self.axis = -1
+
+
 if __name__ == '__main__':
     unittest.main()