Feat: Normalize TableMetadata (apache#611)

* Normalize Table Metadata

* Improve readability & comments

Author: c-thiel

crates/catalog/rest/tests/rest_catalog_test.rs

@@ -293,12 +293,8 @@ async fn test_create_table() {
     assert_eq!(table.metadata().format_version(), FormatVersion::V2);
     assert!(table.metadata().current_snapshot().is_none());
     assert!(table.metadata().history().is_empty());
-    assert!(table.metadata().default_sort_order().unwrap().is_unsorted());
-    assert!(table
-        .metadata()
-        .default_partition_spec()
-        .unwrap()
-        .is_unpartitioned());
+    assert!(table.metadata().default_sort_order().is_unsorted());
+    assert!(table.metadata().default_partition_spec().is_unpartitioned());
 }
 
 #[tokio::test]

crates/iceberg/src/io/object_cache.rs

@@ -252,7 +252,7 @@ mod tests {
         async fn setup_manifest_files(&mut self) {
             let current_snapshot = self.table.metadata().current_snapshot().unwrap();
             let current_schema = current_snapshot.schema(self.table.metadata()).unwrap();
-            let current_partition_spec = self.table.metadata().default_partition_spec().unwrap();
+            let current_partition_spec = self.table.metadata().default_partition_spec();
 
             // Write data files
             let data_file_manifest = ManifestWriter::new(

crates/iceberg/src/scan.rs

@@ -979,7 +979,7 @@ mod tests {
                 .parent_snapshot(self.table.metadata())
                 .unwrap();
             let current_schema = current_snapshot.schema(self.table.metadata()).unwrap();
-            let current_partition_spec = self.table.metadata().default_partition_spec().unwrap();
+            let current_partition_spec = self.table.metadata().default_partition_spec();
 
             // Write data files
             let data_file_manifest = ManifestWriter::new(

crates/iceberg/src/spec/sort.rs

@@ -112,7 +112,7 @@ pub struct SortOrder {
 }
 
 impl SortOrder {
-    const UNSORTED_ORDER_ID: i64 = 0;
+    pub(crate) const UNSORTED_ORDER_ID: i64 = 0;
 
     /// Create sort order builder
     pub fn builder() -> SortOrderBuilder {