Add tests of 2022 EITC/ACTC credit results

tests/expected_taxcalc_results_2022.yaml

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+# Expected 2022 EITC and ACTC aggregates from IRS Statistics of Income
+# Publication 1304 (2022), Table A.
+#
+# DATA SOURCE
+#   Internal Revenue Service, "Statistics of Income — 2022 Individual
+#   Income Tax Returns," Publication 1304, Table A — "Selected Income
+#   and Tax Items, by Size and Accumulated Size of Adjusted Gross Income"
+#
+# DEFINITIONS
+#   n_returns_mil  : Number of returns with a positive credit amount (millions).
+#   amount_bil     : Total credit amount (billions of dollars).
+#
+# NOTES
+#   EITC = Earned Income Credit (refundable); taxcalc variable "eitc".
+#   ACTC = Additional Child Tax Credit (refundable); taxcalc variable "c11070".
+
+eitc:
+  n_returns_mil: 24.09
+  amount_bil: 60.07
+
+actc:
+  n_returns_mil: 18.08
+  amount_bil: 34.84

tests/test_taxcalc_results_2022.py

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+"""
+Test that 2022 Tax-Calculator results for EITC and ACTC match
+IRS Statistics of Income (SOI) Publication 1304 aggregates.
+
+Comparisons (all tax units, year 2022):
+  - Earned Income Credit (EITC): count (millions) and amount (billions)
+  - Additional Child Tax Credit (ACTC): count (millions) and amount (billions)
+"""
+
+import yaml
+import pytest
+import taxcalc
+
+from tmd.imputation_assumptions import TAXYEAR, SOI_IITAX_SPEC, CREDIT_CLAIMING
+
+OLD_CREDIT_CLAIMING = False
+CLAIM_PROB_SCALE = {
+    "eitc": 1.04,
+    "actc": 1.57,
+}
+NEW_CREDIT_CLAIMING = {
+    "eitc_claim_prob_scale": {"2022": CLAIM_PROB_SCALE["eitc"]},
+    "actc_claim_prob_scale": {"2022": CLAIM_PROB_SCALE["actc"]},
+}
+MAX_RELATIVE_TOLERANCE = {
+    "n_returns_mil": 0.07,
+    "amount_bil": 0.002,
+}
+
+
+@pytest.mark.skipif(
+    TAXYEAR != 2022,
+    reason="expected values are calibrated to TAXYEAR=2022",
+)
+def test_taxcalc_results_2022(
+    tests_folder, tmd_variables, tmd_weights_path, tmd_growfactors_path
+):
+    epath = tests_folder / "expected_taxcalc_results_2022.yaml"
+    with open(epath, "r", encoding="utf-8") as f:
+        expect = yaml.safe_load(f)
+
+    pol = taxcalc.Policy()
+    pol.implement_reform(SOI_IITAX_SPEC)
+    if OLD_CREDIT_CLAIMING:
+        pol.implement_reform(CREDIT_CLAIMING)
+    else:
+        pol.implement_reform(NEW_CREDIT_CLAIMING)
+    recs = taxcalc.Records(
+        data=tmd_variables,
+        start_year=TAXYEAR,
+        weights=str(tmd_weights_path),
+        gfactors=taxcalc.GrowFactors(
+            growfactors_filename=str(tmd_growfactors_path)
+        ),
+        adjust_ratios=None,
+        exact_calculations=True,
+        weights_scale=1.0,
+    )
+    sim = taxcalc.Calculator(policy=pol, records=recs)
+    sim.advance_to_year(TAXYEAR)
+    sim.calc_all()
+
+    wt = sim.array("s006")
+    eitc = sim.array("eitc")
+    actc = sim.array("c11070")
+
+    actual = {
+        "eitc": {
+            "n_returns_mil": float((wt * (eitc > 0)).sum() * 1e-6),
+            "amount_bil": float((wt * eitc).sum() * 1e-9),
+        },
+        "actc": {
+            "n_returns_mil": float((wt * (actc > 0)).sum() * 1e-6),
+            "amount_bil": float((wt * actc).sum() * 1e-9),
+        },
+    }
+
+    errors = []
+    for credit in ("eitc", "actc"):
+        for metric in ("n_returns_mil", "amount_bil"):
+            act = actual[credit][metric]
+            exp = expect[credit][metric]
+            rel_diff = act / exp - 1.0
+            if abs(rel_diff) >= MAX_RELATIVE_TOLERANCE[metric]:
+                errors.append(
+                    f"{credit}.{metric}: "
+                    f"act={act:.2f} exp={exp:.2f} "
+                    f"rel_diff={rel_diff:+.4f} "
+                    f"tol={MAX_RELATIVE_TOLERANCE[metric]:.4f}"
+                )
+
+    if errors:
+        raise ValueError(
+            "\nACT-vs-EXP TAXCALC 2022 DIFFERENCES:\n" + "\n".join(errors)
+        )