Scope AR MFJ-2dep low-income table rows added in 2024-2025 to those years

changelog.d/ar-low-income-table-backfill.fixed.md

@@ -0,0 +1 @@
+- Kept the Arkansas MFJ two-or-more-dependents low-income tax table rows added for 2024-2025 out of earlier years; the published tables end at $32,200 (2021) through $34,100 (2023), so incomes above the cutoff use the regular tax table.

policyengine_us/parameters/gov/states/ar/tax/income/rates/low_income_tax_tables/joint/two_or_more_dependents.yaml

@@ -750,22 +750,33 @@ brackets:
       2024-01-01: 754
       2025-01-01: 758
   - threshold:
+      # Rows beyond each year's published cutoff must stay .inf so incomes
+      # above the table fall through to the regular tax table (core
+      # backfills a bracket's first value to the timeline start).
+      2021-01-01: .inf
       2024-01-01: 35_000
       2025-01-01: 35_801
     amount:
+      2021-01-01: .inf
       2024-01-01: 765
       2025-01-01: 769
   - threshold:
+      2021-01-01: .inf
       2024-01-01: 35_100
       2025-01-01: 35_901
     amount:
+      2021-01-01: .inf
       2024-01-01: .inf
       2025-01-01: 779
   - threshold:
+      2021-01-01: .inf
       2025-01-01: 36_001
     amount:
+      2021-01-01: .inf
       2025-01-01: 790
   - threshold:
+      2021-01-01: .inf
       2025-01-01: 36_101
     amount:
+      2021-01-01: .inf
       2025-01-01: .inf

policyengine_us/tests/policy/baseline/gov/states/ar/tax/income/ar_income_tax_before_non_refundable_credits_joint.yaml

@@ -121,3 +121,81 @@
     # Low income cap: 5_000
     # min(1_530, 5_000) = 1_530
     ar_income_tax_before_non_refundable_credits_joint: 1_530
+
+- name: AR 2021 MFJ with two dependents just above the low-income table cutoff uses the regular table (pe-us 9024)
+  period: 2021
+  absolute_error_margin: 1
+  input:
+    people:
+      head:
+        age: 40
+        employment_income: 35_050
+      spouse:
+        age: 40
+      child1:
+        age: 10
+      child2:
+        age: 8
+    tax_units:
+      tax_unit:
+        members: [head, spouse, child1, child2]
+    households:
+      household:
+        members: [head, spouse, child1, child2]
+        state_code: AR
+  output:
+    # 2021 MFJ 2+ dependents low-income table ends at $32,200
+    # ("Above $32,200 use Standard or Itemized Deductions and Regular
+    # Income Tax Table"); regular table: 0.05 x 30,650 - 439.96 = 1,092.54.
+    # Before the fix a leaked 2024 row returned $765.
+    ar_income_tax_before_non_refundable_credits_joint: [1_092.54, 0, 0, 0]
+
+- name: AR 2021 MFJ with two dependents inside the low-income table keeps its table amount (monotonicity companion, pe-us 9024)
+  period: 2021
+  absolute_error_margin: 1
+  input:
+    people:
+      head:
+        age: 40
+        employment_income: 31_950
+      spouse:
+        age: 40
+      child1:
+        age: 10
+      child2:
+        age: 8
+    tax_units:
+      tax_unit:
+        members: [head, spouse, child1, child2]
+    households:
+      household:
+        members: [head, spouse, child1, child2]
+        state_code: AR
+  output:
+    # 2021 published row $31,901-$32,000 -> $921 (TaxTables_2021.pdf)
+    ar_income_tax_before_non_refundable_credits_joint: [921, 0, 0, 0]
+
+- name: AR 2024 MFJ with two dependents at the published last table row still gets 765 (pe-us 9024)
+  period: 2024
+  absolute_error_margin: 1
+  input:
+    people:
+      head:
+        age: 40
+        employment_income: 35_050
+      spouse:
+        age: 40
+      child1:
+        age: 10
+      child2:
+        age: 8
+    tax_units:
+      tax_unit:
+        members: [head, spouse, child1, child2]
+    households:
+      household:
+        members: [head, spouse, child1, child2]
+        state_code: AR
+  output:
+    # 2024 published last row $35,001-$35,100 -> $765
+    ar_income_tax_before_non_refundable_credits_joint: [765, 0, 0, 0]