From: Scott Worley Date: Thu, 23 May 2019 20:48:06 +0000 (-0700) Subject: Test with normalized tax tables X-Git-Tag: v1.0~15 X-Git-Url: http://git.scottworley.com/inverse-tax/commitdiff_plain/a659a4f09cf859b2a63dc5c15f0d4589220c9a83?hp=1c6e40691d86539d80018aa8fc495272b900c4c4 Test with normalized tax tables --- diff --git a/tax.js b/tax.js index d26db5f..7f32f74 100644 --- a/tax.js +++ b/tax.js @@ -7,11 +7,15 @@ function parse_table(as_text) { return as_text.trim().split('\n').map(parse_line); } -function parse_tax_table(as_text) { - return parse_table(as_text).map(([start, rate], i, table) => +function tax_table_from_table(table) { + return table.map(([start, rate], i, table) => [start, i < table.length - 1 ? table[i+1][0] : Infinity, rate / 100.0]); } +function parse_tax_table(as_text) { + return tax_table_from_table(parse_table(as_text)); +} + function sum(nums) { return nums.reduce((total, num) => total + num, 0); } diff --git a/tax.test.js b/tax.test.js index 48f2e0d..b495918 100644 --- a/tax.test.js +++ b/tax.test.js @@ -6,15 +6,22 @@ function test(description, f) { f(); } +function near(a, b, epsilon = 1e-6) { + return Math.abs(a - b) < epsilon; +} + 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)); +function make_random_tax_table() { + function make_random_table(min_threshold) { + if (rand(2)) return []; + const start = min_threshold === undefined ? rand() : min_threshold; + const end = start + 1 + rand(); + return [[start, rand()]].concat(make_random_table(end)); + } + return tax_table_from_table(make_random_table()); } test("parse tax table", () => { @@ -41,7 +48,7 @@ test("merge tax tables", () => { 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)); + assert.ok(near(tax(t1, income) + tax(t2, income), tax(combined, income))); } } });