Enable empty_file integration test by fixing MapArray children names

tests/integration/main.rs

@@ -55,12 +55,6 @@ fn column_projection() {
     test_expected_file("TestOrcFile.columnProjection");
 }
 
-#[test]
-#[ignore] // TODO: nullable difference
-fn empty_file() {
-    test_expected_file("TestOrcFile.emptyFile");
-}
-
 #[test]
 #[ignore] // TODO: Why?
 fn meta_data() {
@@ -111,6 +105,50 @@ fn test1() {
     assert_eq!(actual_batch, expected_batch);
 }
 
+#[test]
+fn empty_file() {
+    let actual_batch = read_orc_file("TestOrcFile.emptyFile");
+    let expected_batch = read_feather_file("TestOrcFile.emptyFile");
+
+    // Super ugly code to rename the "key" and "value" in PyArrow MapArray to
+    // "keys" and "values" which arrow-rs does
+    // TODO: surely there is some better way to handle this?
+    let mut fields = expected_batch.schema().fields[..11].to_vec();
+    let entries_fields: Fields = vec![
+        Field::new("keys", DataType::Utf8, false),
+        Field::new(
+            "values",
+            DataType::Struct(
+                vec![
+                    Field::new("int1", DataType::Int32, true),
+                    Field::new("string1", DataType::Utf8, true),
+                ]
+                .into(),
+            ),
+            true,
+        ),
+    ]
+    .into();
+    let entries_field = Arc::new(Field::new_struct("entries", entries_fields.clone(), false));
+    let map_field = Field::new("map", DataType::Map(entries_field.clone(), false), true);
+    fields.push(Arc::new(map_field));
+    let schema = Arc::new(Schema::new(fields));
+    let mut columns = expected_batch.columns()[..11].to_vec();
+    // Have to destruct the MapArray inorder to reconstruct with correct names for
+    // MapArray struct children
+    let map_array = expected_batch.column(11).as_map().clone();
+    let (_, offsets, entries, nulls, ordered) = map_array.into_parts();
+    let entries = {
+        let (_, arrays, nulls) = entries.into_parts();
+        StructArray::new(entries_fields, arrays, nulls)
+    };
+    let map_array = MapArray::new(entries_field, offsets, entries, nulls, ordered);
+    columns.push(Arc::new(map_array));
+    let expected_batch = RecordBatch::try_new(schema, columns).unwrap();
+
+    assert_eq!(actual_batch, expected_batch);
+}
+
 #[test]
 #[ignore] // TODO: Incorrect timezone + representation differs
 fn test_date_1900() {