From: Scott Worley Date: Thu, 23 May 2019 09:21:14 +0000 (-0700) Subject: Test merge_tax_tables X-Git-Tag: v1.0~19 X-Git-Url: http://git.scottworley.com/inverse-tax/commitdiff_plain/26460571b7a61f69a90d2bb3152774f7badbe734?ds=sidebyside Test merge_tax_tables --- diff --git a/tax.js b/tax.js index 2b5bd4a..2319d21 100644 --- a/tax.js +++ b/tax.js @@ -28,8 +28,8 @@ function apply_deductible(table, deductible) { function merge_tax_tables(t1, t2) { if (t1.length == 0) return t2; if (t2.length == 0) return t1; - [start1, end1, rate1] = t1[0]; - [start2, end2, rate2] = t2[0]; + const [start1, end1, rate1] = t1[0]; + const [start2, end2, rate2] = t2[0]; if (start1 == start2) { if (end1 == end2) { return [[start1, end1, rate1 + rate2]].concat(merge_tax_tables(t1.slice(1), t2.slice(1))); diff --git a/tax.test.js b/tax.test.js index 6fcc15c..067ca91 100644 --- a/tax.test.js +++ b/tax.test.js @@ -22,3 +22,24 @@ test("sum", () => { test("tax", () => { assert.strictEqual(tax([[10, 100, .01], [100, Infinity, .1]], 150), 5.9); }); + +test("merge tax tables", () => { + function rand(limit = 100) { + return Math.round(Math.random() * limit); + } + function make_random_tax_table(min_threshold) { + if (rand(2)) return []; + const start = min_threshold === undefined ? rand() : min_threshold; + const end = start + 1 + rand(); + return [[start, end, rand()]].concat(make_random_tax_table(end)); + } + for (var i = 0; i < 1000; i++) { + const t1 = make_random_tax_table(); + const t2 = make_random_tax_table(); + const combined = merge_tax_tables(t1, t2); + for (var j = 0; j < 10; j++) { + const income = rand(250); + assert.strictEqual(tax(t1, income) + tax(t2, income), tax(combined, income)); + } + } +});