feat(payments): filter candidates by DNI distance

tests/Unit/Purchase/DniDistanceServiceTest.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace Tests\Unit\Purchase;
+
+use App\Domains\Purchase\Services\DniDistanceService;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+
+class DniDistanceServiceTest extends TestCase
+{
+    /** @return iterable<string, array{string, string, int}> */
+    public static function distances(): iterable
+    {
+        yield 'exact' => ['40123456', '40123456', 0];
+        yield 'leading transposition' => ['40123456', '04123456', 1];
+        yield 'trailing transposition' => ['40123456', '40123465', 1];
+        yield 'single substitution' => ['40123456', '40123856', 1];
+        yield 'substitution and transposition' => ['12345678', '12345087', 2];
+        yield 'seven digits normalized with leading zero' => ['04123456', '4123456', 0];
+        yield 'more than two edits' => ['40123456', '87654321', 7];
+    }
+
+    #[DataProvider('distances')]
+    public function test_it_calculates_damerau_levenshtein_distance(
+        string $left,
+        string $right,
+        int $expected,
+    ): void {
+        $this->assertSame($expected, (new DniDistanceService)->distance($left, $right));
+    }
+}