Copy state pension fixes

changelog_entry.yaml

@@ -1,4 +1,4 @@
 - bump: patch
   changes:
     fixed:
-      - Parameterize age 35 threshold in LHA shared accommodation rules
+      - Basic state pension calculation.

policyengine_uk/tests/policy/baseline/gov/dwp/basic_state_pension.yaml

@@ -0,0 +1,44 @@
+- name: Basic state pension calculation with normal parameters
+  period: 2021
+  input:
+    people:
+      person1:
+        state_pension_reported: 5000
+        state_pension_type: BASIC
+        age: 70
+  output:
+    basic_state_pension: 5000  # Should be capped at the minimum of reported and maximum
+
+- name: Basic state pension caps at maximum when reported exceeds maximum
+  period: 2021
+  input:
+    people:
+      person1:
+        state_pension_reported: 10000  # Higher than maximum
+        state_pension_type: BASIC
+        age: 70
+  output:
+    basic_state_pension: 7155.2  # Should be capped at maximum (137.60 * 52)
+
+- name: Non-basic state pension not affected by basic pension maximum
+  period: 2021
+  input:
+    people:
+      person1:
+        state_pension_reported: 5000
+        state_pension_type: NEW  # Not basic pension
+        age: 70
+  output:
+    basic_state_pension: 5000  # Should not be affected by basic pension maximum
+
+- name: Basic state pension should be zero when maximum is zero
+  period: 2021
+  input:
+    gov.dwp.state_pension.basic_state_pension.amount: 0
+    people:
+      person1:
+        state_pension_reported: 5000
+        state_pension_type: BASIC
+        age: 70
+  output:
+    basic_state_pension: 0

policyengine_uk/variables/gov/dwp/basic_state_pension.py

@@ -10,20 +10,32 @@ class basic_state_pension(Variable):
 
     def formula(person, period, parameters):
         simulation = person.simulation
-        if simulation.dataset is None:
-            return 0
+        has_dataset = simulation.dataset is not None
+
+        data_year = simulation.dataset.time_period if has_dataset else period
+
+        reported = where(
+            has_dataset,
+            person("state_pension_reported", data_year) / WEEKS_IN_YEAR,
+            person("state_pension_reported", period) / WEEKS_IN_YEAR,
+        )
 
-        data_year = simulation.dataset.time_period
-        reported = person("state_pension_reported", data_year) / WEEKS_IN_YEAR
         type = person("state_pension_type", period)
         maximum_basic_sp = parameters(
             data_year
         ).gov.dwp.state_pension.basic_state_pension.amount
         amount_in_data_year = where(
             type == type.possible_values.BASIC,
             min_(reported, maximum_basic_sp),
-            0,
+            reported,
         )
-        triple_lock = parameters.gov.economic_assumptions.indices.triple_lock
-        uprating_since_data_year = triple_lock(period) / triple_lock(data_year)
-        return amount_in_data_year * uprating_since_data_year * WEEKS_IN_YEAR
+        uprating_factor = where(
+            has_dataset,
+            parameters.gov.economic_assumptions.yoy_growth.triple_lock(period)
+            / parameters.gov.economic_assumptions.yoy_growth.triple_lock(
+                data_year
+            ),
+            1,
+        )
+
+        return amount_in_data_year * uprating_factor * WEEKS_IN_YEAR