Fixed GetDatasetSize for TextFile

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/text_file_op.cc

@@ -529,7 +529,7 @@ Status TextFileOp::GetDatasetSize(int64_t *dataset_size) {
   int64_t num_rows, sample_size;
   sample_size = total_rows_;
   if (num_rows_per_shard_ <= 0) RETURN_IF_NOT_OK(CalculateNumRowsPerShard());
-  num_rows = total_rows_;
+  num_rows = num_rows_per_shard_;
   *dataset_size = sample_size > 0 ? std::min(num_rows, sample_size) : num_rows;
   dataset_size_ = *dataset_size;
   return Status::OK();

tests/ut/cpp/dataset/c_api_dataset_textfile_test.cc

@@ -105,6 +105,10 @@ TEST_F(MindDataTestPipeline, TestTextFileGetters) {
   EXPECT_EQ(ds->GetDatasetSize(), 2);
   EXPECT_EQ(ds->GetColumnNames(), column_names);
 
+  ds = TextFile({tf_file1}, 0);
+  EXPECT_NE(ds, nullptr);
+
+  EXPECT_EQ(ds->GetDatasetSize(), 3);
   // Restore configuration
   GlobalContext::config_manager()->set_seed(original_seed);
   GlobalContext::config_manager()->set_num_parallel_workers(original_num_parallel_workers);