Steuertabellen 2026 für DE, AT, CH (Bund) und LI (Land) zu tax

test/rdb_test.rb

@@ -723,3 +723,40 @@ class PickTest < RdbCase
     assert_equal '', table
   end
 end
+
+class TaxTablesTest < RdbCase
+  def tax(income, table) = rdb('tax', income.to_s, file: table).to_i
+
+  def test_at_2026
+    assert_equal 0, tax(13_539, 'taxAT2026')
+    assert_equal 11_447, tax(50_000, 'taxAT2026') # 6 030.40 + 13 542 * 40 %
+    assert_equal 33_818, tax(100_000, 'taxAT2026')
+  end
+
+  def test_ch_federal_2026
+    assert_equal 0, tax(15_200, 'taxCH2026')
+    assert_equal 401, tax(50_000, 'taxCH2026')
+    assert_equal 2684, tax(100_000, 'taxCH2026')
+    assert_equal 91_310, tax(794_000, 'taxCH2026')
+  end
+
+  def test_li_landessteuer_2026
+    assert_equal 996, tax(50_000, 'taxLI2026')   # 0,04 * x - 1 004
+    assert_equal 3256, tax(100_000, 'taxLI2026') # 0,05 * x - 1 744
+    assert_equal 10_464, tax(211_400, 'taxLI2026')
+    assert_equal 0, tax(15_855, 'taxLI2026')
+  end
+
+  # § 32a EStG: the table is a straight-line approximation of the curved zones
+  def test_de_2026_follows_the_formula
+    [12_348, 14_000, 17_799, 20_000, 33_333, 50_000, 69_878, 100_000, 277_825, 300_000].each do |x|
+      exact = if x <= 12_348 then 0
+              elsif x <= 17_799 then y = (x - 12_348) / 10_000.0; ((914.51 * y) + 1400) * y
+              elsif x <= 69_878 then z = (x - 17_799) / 10_000.0; (((173.10 * z) + 2397) * z) + 1034.87
+              elsif x <= 277_825 then (0.42 * x) - 11_135.63
+              else (0.45 * x) - 19_470.38
+              end
+      assert_in_delta exact.floor, tax(x, 'taxDE2026'), 1, "income #{x}"
+    end
+  end
+end