update recordio unittest

Author: JiayiFeng

paddle/fluid/framework/reader.cc

@@ -22,7 +22,9 @@ FileReader::FileReader(const std::vector<DDim> &dims) : dims_(dims) {}
 
 void FileReader::ReadNext(std::vector<LoDTensor> *out) {
   ReadNextImpl(out);
-  PADDLE_ENFORCE_EQ(out->size(), dims_.size());
+  if (out->empty()) {
+    return;
+  }
   for (size_t i = 0; i < dims_.size(); ++i) {
     auto &actual = out->at(i).dims();
     auto &expect = dims_[i];

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

@@ -65,8 +65,14 @@ def test_main(self, decorator_callback=None):
 
             # train a pass
             batch_id = 0
-            while not data_file.eof():
-                tmp, = exe.run(fetch_list=[avg_loss])
+            while True:
+                ex = None
+                try:
+                    tmp, = exe.run(fetch_list=[avg_loss])
+                except fluid.core.EnforceNotMet as ex:
+                    self.assertIn("There is no next data.", ex.message)
+                    break
+
                 avg_loss_np.append(tmp)
                 batch_id += 1
             data_file.reset()