From 816caad02e00ef6744ed9d5543363a397f3bf877 Mon Sep 17 00:00:00 2001
From: Max Ghenis <mghenis@gmail.com>
Date: Tue, 7 Apr 2026 12:31:14 -0400
Subject: [PATCH] Replace high-value surcharge test with YAML policy tests

---
 .../high_value_council_tax_surcharge.yaml     | 51 ++++++++++++++
 .../test_high_value_council_tax_surcharge.py  | 70 -------------------
 2 files changed, 51 insertions(+), 70 deletions(-)
 create mode 100644 policyengine_uk/tests/policy/baseline/gov/hmrc/council_tax/high_value_council_tax_surcharge.yaml
 delete mode 100644 policyengine_uk/tests/test_high_value_council_tax_surcharge.py

diff --git a/policyengine_uk/tests/policy/baseline/gov/hmrc/council_tax/high_value_council_tax_surcharge.yaml b/policyengine_uk/tests/policy/baseline/gov/hmrc/council_tax/high_value_council_tax_surcharge.yaml
new file mode 100644
index 000000000..94b896ccb
--- /dev/null
+++ b/policyengine_uk/tests/policy/baseline/gov/hmrc/council_tax/high_value_council_tax_surcharge.yaml
@@ -0,0 +1,51 @@
+- name: High value council tax surcharge starts in 2028
+  period: 2027
+  input:
+    region: LONDON
+    main_residence_value: 3_000_000
+    main_residential_property_purchased: 0
+    council_tax: 0
+    household_owns_tv: false
+    gov.hmrc.stamp_duty.property_sale_rate: 0
+  output:
+    high_value_council_tax_surcharge: 0
+- name: High value council tax surcharge applies in England and flows into aggregates
+  period: 2028
+  input:
+    region: LONDON
+    main_residence_value: 2_554_326.811538164
+    main_residential_property_purchased: 0
+    council_tax: 0
+    household_owns_tv: false
+    gov.hmrc.stamp_duty.property_sale_rate: 0
+  output:
+    high_value_council_tax_surcharge: 2_500
+    household_tax: 2_500
+    gov_tax: 2_500
+- name: High value council tax surcharge is uprated from 2029
+  period: 2029
+  absolute_error_margin: 0.01
+  input:
+    region: LONDON
+    main_residence_value: 2_629_940.453174542
+    main_residential_property_purchased: 0
+    council_tax: 0
+    household_owns_tv: false
+    gov.hmrc.stamp_duty.property_sale_rate: 0
+  output:
+    high_value_council_tax_surcharge: 2_550
+    household_tax: 2_550
+    gov_tax: 2_550
+- name: High value council tax surcharge only applies in England
+  period: 2028
+  input:
+    region: SCOTLAND
+    main_residence_value: 7_000_000
+    main_residential_property_purchased: 0
+    council_tax: 0
+    household_owns_tv: false
+    gov.hmrc.stamp_duty.property_sale_rate: 0
+  output:
+    high_value_council_tax_surcharge: 0
+    household_tax: 0
+    gov_tax: 0
diff --git a/policyengine_uk/tests/test_high_value_council_tax_surcharge.py b/policyengine_uk/tests/test_high_value_council_tax_surcharge.py
deleted file mode 100644
index 706af054a..000000000
--- a/policyengine_uk/tests/test_high_value_council_tax_surcharge.py
+++ /dev/null
@@ -1,70 +0,0 @@
-import pytest
-
-from policyengine_uk import Simulation
-from policyengine_uk.variables.gov.gov_tax import gov_tax
-from policyengine_uk.variables.gov.hmrc.household_tax import household_tax
-
-
-def _homeowner(main_residence_value: float, region: str = "LONDON") -> dict:
-    return {
-        "people": {
-            "person": {
-                "age": {2026: 45, 2028: 47, 2029: 48},
-                "employment_income": {2028: 0, 2029: 0},
-            }
-        },
-        "benunits": {"benunit": {"members": ["person"]}},
-        "households": {
-            "household": {
-                "members": ["person"],
-                "region": {2028: region, 2029: region},
-                "main_residence_value": {2026: main_residence_value},
-            }
-        },
-    }
-
-
-def test_high_value_council_tax_surcharge_starts_in_2028():
-    sim = Simulation(situation=_homeowner(2_400_000))
-
-    assert sim.calculate("high_value_council_tax_surcharge", 2027)[0] == 0
-    assert sim.calculate("high_value_council_tax_surcharge", 2028)[0] == 2_500
-
-
-def test_high_value_council_tax_surcharge_is_uprated_from_2029():
-    sim = Simulation(situation=_homeowner(2_400_000))
-    current = sim.tax_benefit_system.parameters("2029")
-    previous = sim.tax_benefit_system.parameters("2028")
-    expected_2029 = (
-        2_500
-        * float(current.gov.benefit_uprating_cpi)
-        / float(previous.gov.benefit_uprating_cpi)
-    )
-
-    assert sim.calculate("high_value_council_tax_surcharge", 2029)[0] == pytest.approx(
-        expected_2029
-    )
-
-
-def test_high_value_council_tax_surcharge_flows_into_tax_aggregates():
-    sim = Simulation(situation=_homeowner(2_400_000))
-
-    other_household_taxes = sum(
-        sim.calculate(variable, 2028)[0]
-        for variable in household_tax.adds
-        if variable != "high_value_council_tax_surcharge"
-    )
-    other_government_taxes = sum(
-        sim.calculate(variable, 2028)[0]
-        for variable in gov_tax.adds
-        if variable != "high_value_council_tax_surcharge"
-    )
-
-    assert sim.calculate("household_tax", 2028)[0] - other_household_taxes == 2_500
-    assert sim.calculate("gov_tax", 2028)[0] - other_government_taxes == 2_500
-
-
-def test_high_value_council_tax_surcharge_only_applies_in_england():
-    sim = Simulation(situation=_homeowner(6_000_000, region="SCOTLAND"))
-
-    assert sim.calculate("high_value_council_tax_surcharge", 2028)[0] == 0