test: assert null variant keys are dropped from the context

Author: gagantrivedi

tests/test_mappers.py

@@ -40,3 +40,18 @@ def test_map_environment_document_to_context__keyed_variant__carries_key() -> No
     # Then
     variants = context["features"]["mv_feature"]["variants"]
     assert variants[0]["key"] == "variant_a"
+
+
+def test_map_environment_document_to_context__null_variant_key__drops_key() -> None:
+    # Given - an unkeyed variant is serialised with a null key
+    environment = _environment_with_keyed_variant()
+    environment["feature_states"][0]["multivariate_feature_state_values"][0][
+        "multivariate_feature_option"
+    ]["key"] = None
+
+    # When
+    context = map_environment_document_to_context(environment)
+
+    # Then - the null key is dropped, treated as no key
+    variants = context["features"]["mv_feature"]["variants"]
+    assert "key" not in variants[0]