Add test coverage for register_correlation_hook_with_master_record

tests/modules/test_module.py

@@ -14,6 +14,22 @@ def modify_value(_: str, record: dict, attr: str, value):
     record[attr] = value
 
 
+def use_master_record(
+    _: str, record: dict, master_record: dict, target_attr: str, source_attr: str
+):
+    """Hook that uses master record to copy a value from master to snapshot.
+
+    Only applies when source attribute in master record has value starting with "master_"
+    to avoid interfering with other test cases.
+    """
+    if source_attr in master_record:
+        # Get the value from master record
+        master_value = master_record[source_attr].get("v", None)
+        if master_value is not None and str(master_value).startswith("master_"):
+            # Append a suffix to demonstrate master record was used
+            record[target_attr] = f"{master_value}_from_master"
+
+
 dummy_hook_abc = update_wrapper(partial(modify_value, attr="data2", value="abc"), modify_value)
 dummy_hook_def = update_wrapper(partial(modify_value, attr="data1", value="def"), modify_value)
 
@@ -67,3 +83,15 @@ def __init__(
             depends_on=[],
             may_change=[["data1"]],
         )
+
+        # Testing register_correlation_hook_with_master_record
+        # This hook should copy data1 from master record to data2 with a suffix
+        registrar.register_correlation_hook_with_master_record(
+            update_wrapper(
+                partial(use_master_record, target_attr="data2", source_attr="data1"),
+                use_master_record,
+            ),
+            "A",
+            depends_on=[],
+            may_change=[["data2"]],
+        )

tests/test_api/test_snapshots.py

@@ -42,6 +42,9 @@ def make_dp(type, id, attr, v, time=False):
             make_dp("C", "c1", "ds", {"eid": "d1"}, time=True),
             make_dp("C", "c1", "data1", "inita"),
             make_dp("C", "c1", "data2", "inita"),
+            # For test_master_record_hook (A-423)
+            make_dp("A", 423, "data1", "master_test"),
+            make_dp("A", 423, "data2", "placeholder"),
         ]
         res = cls.push_datapoints(entity_datapoints)
         if res.status_code != 200:
@@ -79,3 +82,17 @@ def test_hook_dependency_value_forwarding(self):
             for snapshot in data.snapshots:
                 self.assertEqual(snapshot["data1"], "modifd")
                 self.assertEqual(snapshot["data2"], "modifc")
+
+    def test_master_record_hook(self):
+        """
+        Test that hooks registered via register_correlation_hook_with_master_record
+        correctly receive the master record parameter.
+        """
+        # Entity A-423 has data1="master_test" in its master record
+        # The master record hook should copy data1 from master and append "_from_master"
+        data = self.get_entity_data("entity/A/423", EntityEidData)
+        self.assertGreater(len(data.snapshots), 0)
+        for snapshot in data.snapshots:
+            self.assertEqual(snapshot["data1"], "master_test")
+            # The hook should have set data2 to data1 from master record + "_from_master"
+            self.assertEqual(snapshot["data2"], "master_test_from_master")