Add tests for nested decimal arrays (#2254)

parquet/src/arrow/arrow_reader.rs

@@ -397,6 +397,7 @@ mod tests {
     use tempfile::tempfile;
 
     use arrow::array::*;
+    use arrow::buffer::Buffer;
     use arrow::datatypes::{DataType as ArrowDataType, Field, Schema};
     use arrow::error::Result as ArrowResult;
     use arrow::record_batch::{RecordBatch, RecordBatchReader};
@@ -729,6 +730,87 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_decimal_nullable_struct() {
+        let decimals = Decimal128Array::from_iter_values([1, 2, 3, 4, 5, 6, 7, 8]);
+
+        let data = ArrayDataBuilder::new(ArrowDataType::Struct(vec![Field::new(
+            "decimals",
+            decimals.data_type().clone(),
+            false,
+        )]))
+        .len(8)
+        .null_bit_buffer(Some(Buffer::from(&[0b11101111])))
+        .child_data(vec![decimals.into_data()])
+        .build()
+        .unwrap();
+
+        let written = RecordBatch::try_from_iter([(
+            "struct",
+            Arc::new(StructArray::from(data)) as ArrayRef,
+        )])
+        .unwrap();
+
+        let mut buffer = Vec::with_capacity(1024);
+        let mut writer =
+            ArrowWriter::try_new(&mut buffer, written.schema(), None).unwrap();
+        writer.write(&written).unwrap();
+        writer.close().unwrap();
+
+        let read = ParquetFileArrowReader::try_new(Bytes::from(buffer))
+            .unwrap()
+            .get_record_reader(3)
+            .unwrap()
+            .collect::<ArrowResult<Vec<_>>>()
+            .unwrap();
+
+        assert_eq!(&written.slice(0, 3), &read[0]);
+        assert_eq!(&written.slice(3, 3), &read[1]);
+        assert_eq!(&written.slice(6, 2), &read[2]);
+    }
+
+    #[test]
+    #[ignore] // https://github.com/apache/arrow-rs/issues/2253
+    fn test_decimal_list() {
+        let decimals = Decimal128Array::from_iter_values([1, 2, 3, 4, 5, 6, 7, 8]);
+
+        // [[], [1], [2, 3], null, [4], null, [6, 7, 8]]
+        let data = ArrayDataBuilder::new(ArrowDataType::List(Box::new(Field::new(
+            "item",
+            decimals.data_type().clone(),
+            false,
+        ))))
+        .len(7)
+        .add_buffer(Buffer::from_iter([0_i32, 0, 1, 3, 3, 4, 5, 8]))
+        .null_bit_buffer(Some(Buffer::from(&[0b01010111])))
+        .child_data(vec![decimals.into_data()])
+        .build()
+        .unwrap();
+
+        let written = RecordBatch::try_from_iter([(
+            "list",
+            Arc::new(ListArray::from(data)) as ArrayRef,
+        )])
+        .unwrap();
+
+        let mut buffer = Vec::with_capacity(1024);
+        let mut writer =
+            ArrowWriter::try_new(&mut buffer, written.schema(), None).unwrap();
+        writer.write(&written).unwrap();
+        writer.close().unwrap();
+
+        let read = ParquetFileArrowReader::try_new(Bytes::from(buffer))
+            .unwrap()
+            .get_record_reader(3)
+            .unwrap()
+            .collect::<ArrowResult<Vec<_>>>()
+            .unwrap();
+
+        assert_eq!(&written.slice(0, 3), &read[0]);
+        assert_eq!(&written.slice(3, 3), &read[1]);
+        assert_eq!(&written.slice(6, 1), &read[2]);
+    }
+
     #[test]
     fn test_read_decimal_file() {
         use arrow::array::Decimal128Array;