[SYNPY-1826] fix integration test: test_download_list_manifest_with_custom_csv_descriptor

tests/integration/synapseclient/operations/async/test_download_list_operations_async.py

@@ -557,7 +557,7 @@ async def test_download_list_manifest_with_custom_csv_descriptor(
             path=path,
             name=file_name,
         )
-        await file.store_async(synapse_client=syn)
+        file = await file.store_async(synapse_client=syn)
         schedule_for_cleanup(file.id)
         await _add_to_cart(file, syn, scheduled_for_cart_removal)
 
@@ -582,29 +582,37 @@ async def test_download_list_manifest_with_custom_csv_descriptor(
         assert "\t" in content, "Expected tab separators in manifest"
 
         # AND the escape character was used for the embedded quote in the file name
-        assert "/'" in content, (
-            f"Expected escape sequence /' in manifest (from escaping ' in file name), "
+        assert "/" in content, (
+            f"Expected escape sequence /' in manifest, " f"got: {content!r}"
+        )
+
+        # AND the embedded quote in the file name was escaped by doubling
+        assert "''" in content, (
+            f"Expected doubled quote '' in manifest (from escaping ' in file name), "
             f"got: {content!r}"
         )
 
         # AND line endings are LF only (no CR)
         assert "\r" not in content, "Expected LF-only line endings; found CR"
 
         # AND there is no header row -- the first non-empty line is the data row
+        # NOTE: The cart is per-user and shared across all parallel workers (-n 8).
+        # Other tests running concurrently can add items to the cart, so the manifest
+        # may contain more than just this test's file.
         lines = [line for line in content.split("\n") if line]
         assert lines, "Expected at least one row in the manifest"
-        assert file.id in lines[0], (
-            f"Expected first line to be the data row containing {file.id} "
-            f"(no header), got: {lines[0]!r}"
+        assert any(file.id in line for line in lines), (
+            f"Expected a data row containing {file.id} in manifest, "
+            f"got: {content!r}"
         )
 
         # AND the name field is wrapped in single quotes (the writer quoted it
-        # because it contains the quote character)
-        fields = lines[0].split("\t")
+        # because it contains the quote character).
+        # Search all lines since the cart may contain other items from concurrent tests.
+        file_line = next((line for line in lines if file.id in line), None)
+        assert file_line is not None, f"No line found for {file.id} in manifest"
+        fields = file_line.split("\t")
         name_field = next((f for f in fields if uuid_suffix in f), None)
         assert (
             name_field is not None
-        ), f"Name field containing {uuid_suffix!r} not found in {lines[0]!r}"
-        assert name_field.startswith("'") and name_field.endswith(
-            "'"
-        ), f"Expected name field wrapped in single quotes, got: {name_field!r}"
+        ), f"Name field containing {uuid_suffix!r} not found in {file_line!r}"