[FRONTEND][TENSORFLOW] fix the convertion of sum and add testcase for it (#1654)

* [TENSORFLOW] fix the convertion of sum and add testcase for it

* delete checking tyoe of axis and divide reduce test

nnvm/python/nnvm/frontend/tensorflow.py

@@ -444,6 +444,8 @@ def _lrn():
 def _sum():
     def _impl(inputs, attr, params):
         axis = params.pop(inputs[1].list_output_names()[0]).asnumpy()
+        # convert to tuple for preventing invalid parameter format error
+        axis = tuple(axis)
         return AttrCvt(
             op_name='sum',
             extras={'axis': axis},

nnvm/tests/python/frontend/tensorflow/test_forward.py

@@ -349,6 +349,26 @@ def test_forward_argminmax():
         _test_argx(tf.argmin, data=data, axis=axis)
 
 #######################################################################
+# Reduce
+# ------
+
+def _test_reduce(func, data, **kwargs):
+    """ One iteration of a reduce operation"""
+
+    with tf.Graph().as_default():
+        inp = array_ops.placeholder(shape=data.shape, dtype=data.dtype, name="c0")
+        func(inp, name="reducex0", **kwargs)
+
+        compare_tf_with_tvm(data, 'c0:0', 'reducex0:0')
+
+def test_forward_reduce():
+    data = np.random.uniform(size=(8,4,9)).astype('float32')
+    _test_reduce(tf.reduce_sum, data=data)
+    _test_reduce(tf.reduce_sum, data=data, axis=0)
+    _test_reduce(tf.reduce_sum, data=data, axis=(0,1))    
+
+
+#######################################################################
 # Variable
 # --------
 
@@ -844,6 +864,7 @@ if __name__ == '__main__':
     test_forward_squeeze()
     test_forward_sigmoid()
     test_forward_argminmax()
+    test_forward_reduce()
     if tf.__version__ == '1.4.1':
         _test_forward_concat_v2()
     test_forward_multi_input()