Roman numeral converter

tests/RomanNumeralsConverterTest.php

@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+use App\RomanNumeralsConverter;
+use Assert\AssertionFailedException;
+
+it('converts numbers to roman numerals', function (int $number, string $expected): void {
+    assertSame($expected, RomanNumeralsConverter::convert($number));
+})->with([
+    [1, 'I'],
+    [2, 'II'],
+    [3, 'III'],
+    [4, 'IV'],
+    [5, 'V'],
+    [9, 'IX'],
+    [10, 'X'],
+    [15, 'XV'],
+    [19, 'XIX'],
+    [20, 'XX'],
+    [21, 'XXI'],
+    [40, 'XL'],
+    [50, 'L'],
+    [80, 'LXXX'],
+    [90, 'XC'],
+    [100, 'C'],
+    [110, 'CX'],
+    [400, 'CD'],
+    [500, 'D'],
+    [700, 'DCC'],
+    [900, 'CM'],
+    [1000, 'M'],
+    [1986, 'MCMLXXXVI'],
+    [1990, 'MCMXC'],
+    [2020, 'MMXX'],
+]);
+
+it('cannot convert negative numbers', function (): void {
+    RomanNumeralsConverter::convert(-1);
+})->throws(AssertionFailedException::class, 'Cannot convert negative numbers');