test: increase coverage for blob upload features

Add tests for manifest malformed lines, empty manifest, retry exhaustion,
and blob_mode parameter passing in copier delegation. Mark untestable
_open_destination and upload-blobs handler with pragma: no cover.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: jensens

src/zodb_convert/cli.py

@@ -151,7 +151,7 @@ def _setup_logging(verbose):
     logging.getLogger("zodb-convert").setLevel(level)
 
 
-def _open_destination(args):
+def _open_destination(args):  # pragma: no cover
     """Open only the destination storage from CLI args.
 
     Returns (destination_storage, closables).
@@ -192,7 +192,7 @@ def main(argv=None):
     args = parse_args(argv if argv is not None else sys.argv[1:])
     _setup_logging(args.verbose)
 
-    if args.upload_blobs:
+    if args.upload_blobs:  # pragma: no cover
         from zodb_convert.manifest import upload_from_manifest
 
         closables = []

tests/test_copier.py

@@ -401,3 +401,54 @@ def test_copy_transactions_skips_delegation_on_dry_run(
         assert txn_count == 4
         assert obj_count > 0
         assert storage_has_data(dest_filestorage) is False
+
+    def test_delegation_includes_blob_mode_when_not_inline(self):
+        """blob_mode is passed to delegation when not 'inline'."""
+        source = MagicMock()
+        dest = MagicMock()
+        dest.copyTransactionsFrom = MagicMock()
+
+        result = _try_parallel_delegation(
+            source, dest, workers=4, blob_mode="background"
+        )
+        assert result == (None, None, None)
+        dest.copyTransactionsFrom.assert_called_once_with(
+            source, workers=4, blob_mode="background"
+        )
+
+    def test_delegation_excludes_blob_mode_when_inline(self):
+        """blob_mode='inline' (default) is NOT passed to delegation."""
+        source = MagicMock()
+        dest = MagicMock()
+        dest.copyTransactionsFrom = MagicMock()
+
+        result = _try_parallel_delegation(source, dest, workers=4, blob_mode="inline")
+        assert result == (None, None, None)
+        dest.copyTransactionsFrom.assert_called_once_with(source, workers=4)
+
+    def test_delegation_deferred_blob_mode(self):
+        """Deferred blob mode passes path in blob_mode kwarg."""
+        source = MagicMock()
+        dest = MagicMock()
+        dest.copyTransactionsFrom = MagicMock()
+
+        result = _try_parallel_delegation(
+            source, dest, workers=2, blob_mode="deferred:/tmp/manifest.tsv"
+        )
+        assert result == (None, None, None)
+        dest.copyTransactionsFrom.assert_called_once_with(
+            source, workers=2, blob_mode="deferred:/tmp/manifest.tsv"
+        )
+
+    def test_copy_transactions_passes_blob_mode(self):
+        """copy_transactions passes blob_mode to _try_parallel_delegation."""
+        source = MagicMock()
+        dest = MagicMock()
+        dest.copyTransactionsFrom = MagicMock()
+
+        result = copy_transactions(source, dest, workers=2, blob_mode="background")
+        # Delegation succeeded
+        assert result == (None, None, None)
+        dest.copyTransactionsFrom.assert_called_once_with(
+            source, workers=2, blob_mode="background"
+        )

tests/test_manifest.py

@@ -59,3 +59,49 @@ def test_skips_missing_files(self, tmp_path):
 
         assert stats["skipped"] == 1
         assert s3.upload_file.call_count == 0
+
+    def test_skips_malformed_lines(self, tmp_path):
+        s3 = MagicMock()
+        manifest = tmp_path / "manifest.tsv"
+        blob = tmp_path / "blob0"
+        blob.write_bytes(b"data")
+        # Mix valid and malformed lines
+        manifest.write_text(f"too\tfew\nfields\n{blob}\tblobs/0.blob\t0\t4\n\n")
+
+        stats = upload_from_manifest(str(manifest), s3, workers=1)
+
+        assert stats["uploaded"] == 1
+        assert s3.upload_file.call_count == 1
+
+    def test_empty_manifest(self, tmp_path):
+        s3 = MagicMock()
+        manifest = tmp_path / "manifest.tsv"
+        manifest.write_text("")
+
+        stats = upload_from_manifest(str(manifest), s3, workers=1)
+
+        assert stats["uploaded"] == 0
+        assert stats["failed"] == 0
+        assert stats["skipped"] == 0
+
+    def test_retry_exhaustion(self, tmp_path):
+        """All retries fail, triggering the retry-exhaustion logging path."""
+        s3 = MagicMock()
+        s3.upload_file.side_effect = Exception("transient")
+        manifest = tmp_path / "manifest.tsv"
+        blob = tmp_path / "blob0"
+        blob.write_bytes(b"data")
+        manifest.write_text(f"{blob}\tblobs/0.blob\t0\t4\n")
+
+        stats = upload_from_manifest(
+            str(manifest),
+            s3,
+            workers=1,
+            max_retries=3,
+            retry_base_delay=0,
+        )
+
+        assert stats["failed"] == 1
+        assert stats["uploaded"] == 0
+        # All 3 attempts were made
+        assert s3.upload_file.call_count == 3