fix: accept the ISO-2 country codes when authoring a destination

tests/Model/DestinationDtoTest.php

@@ -0,0 +1,86 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Model;
+
+use App\Model\DestinationDto;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Validator\ConstraintViolationListInterface;
+use Symfony\Component\Validator\Validation;
+
+/**
+ * The stored country moved to ISO-3166-1 alpha-2, but the constraint on this DTO kept the
+ * old BusProNet abbreviations while the form was already offering the new codes. Every
+ * country except Schweiz and Niederlande - the two whose code happens to be unchanged -
+ * was rejected as "Ungültige Auswahl" on save, so a destination could not be created or
+ * edited for Österreich, Deutschland, Frankreich or Italien at all.
+ *
+ * The codes are asserted literally rather than read back off the map they come from, so
+ * that changing the map has to be a deliberate act rather than something a test agrees
+ * with by construction.
+ */
+class DestinationDtoTest extends TestCase
+{
+    public function testTheAuthorableCountriesAreTheIsoCodes(): void
+    {
+        $this->assertSame(['at', 'ch', 'fr', 'it', 'de', 'nl'], DestinationDto::countryCodes());
+    }
+
+    /**
+     * @dataProvider isoCountryCodes
+     */
+    public function testAnIsoCountryCodeIsAccepted(string $code): void
+    {
+        $this->assertCount(0, $this->validateCountry($code));
+    }
+
+    /**
+     * The four that the form offered and the constraint refused.
+     *
+     * @dataProvider busProNetCountryAbbreviations
+     */
+    public function testABusProNetAbbreviationIsNoLongerAccepted(string $abbreviation): void
+    {
+        $this->assertCount(1, $this->validateCountry($abbreviation));
+    }
+
+    /**
+     * MyE&P drops a country it cannot map to two letters, so a destination without one is
+     * a normal row rather than an invalid one.
+     */
+    public function testNoCountryIsAccepted(): void
+    {
+        $this->assertCount(0, $this->validateCountry(null));
+    }
+
+    /**
+     * @return iterable<array{string}>
+     */
+    public static function isoCountryCodes(): iterable
+    {
+        foreach (DestinationDto::countryCodes() as $code) {
+            yield $code => [$code];
+        }
+    }
+
+    /**
+     * @return iterable<array{string}>
+     */
+    public static function busProNetCountryAbbreviations(): iterable
+    {
+        yield 'a' => ['a'];
+        yield 'd' => ['d'];
+        yield 'f' => ['f'];
+        yield 'i' => ['i'];
+    }
+
+    private function validateCountry(?string $country): ConstraintViolationListInterface
+    {
+        return Validation::createValidatorBuilder()
+            ->enableAttributeMapping()
+            ->getValidator()
+            ->validateProperty((new DestinationDto())->setCountry($country), 'country')
+        ;
+    }
+}