Yannick
--- a/tests/unit/fixtures.py
+++ b/tests/unit/fixtures.py
+            """
+            If version is None it will return the latest version. To determine the latest version, two cases:
+              * the version field in the record is not set or None => considered as the latest
+              * the version field set and not None => latest = record with the greater version (basic int comparison)
+            """
+
+            latest = None
            for d in data:
                # CAREFUL: id might be optional in the model (not set on write)
                # Also storage seems to have problematic behavior with id ending in ':'
                if id is not None and (id == d.id or id + ":" == d.id):
                    if version is None or version == d.version:  # Note: version None means latest
-                        return d
+                        if d.version is None:  # no version set in record just return this one
+                            return d
+                        elif latest is None or d.version > latest.version: