data: iter_postings uses Account.

conservancy_beancount/data.py

@@ -86,5 +86,6 @@ class PostingMeta(collections.abc.MutableMapping):
 def iter_postings(txn: Transaction) -> Iterator[Posting]:
     for index, source in enumerate(txn.postings):
         yield source._replace(
+            account=Account(source.account),
             meta=PostingMeta(txn, index, source),
         )

tests/test_data_iter_postings.py

@@ -30,6 +30,7 @@ def simple_txn(index=None, key=None):
 def test_iter_postings(simple_txn):
     for source, post in zip(simple_txn.postings, data.iter_postings(simple_txn)):
         assert all(source[x] == post[x] for x in range(len(source) - 1))
+        assert isinstance(post.account, data.Account)
         assert post.meta['note']  # Only works with PostingMeta
 
 def test_setting_metadata_propagates_to_source(simple_txn):