Add functional tests

tests/Functional/Driver/DBAL6146Test.php

@@ -0,0 +1,85 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\DBAL\Tests\Functional\Driver;
+
+use Doctrine\DBAL\Schema\Column;
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\DBAL\Schema\Table;
+use Doctrine\DBAL\Tests\FunctionalTestCase;
+use Doctrine\DBAL\Tests\TestUtil;
+use Doctrine\DBAL\Types\StringType;
+use PHPUnit\Framework\Attributes\DataProvider;
+
+class DBAL6146Test extends FunctionalTestCase
+{
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        if (TestUtil::isDriverOneOf('pdo_mysql', 'mysqli')) {
+            return;
+        }
+
+        self::markTestSkipped('This test requires the pdo_mysql or the mysqli driver.');
+    }
+
+    /** @return iterable<array{array<string,string>,array<string,string>}> */
+    public static function equivalentCharsetAndCollationProvider(): iterable
+    {
+        yield [[], []];
+        yield [['charset' => 'utf8'], ['charset' => 'utf8']];
+        yield [['charset' => 'utf8'], ['charset' => 'utf8mb3']];
+        yield [['charset' => 'utf8mb3'], ['charset' => 'utf8']];
+        yield [['charset' => 'utf8mb3'], ['charset' => 'utf8mb3']];
+        yield [['collation' => 'utf8_unicode_ci'], ['collation' => 'utf8_unicode_ci']];
+        yield [['collation' => 'utf8_unicode_ci'], ['collation' => 'utf8mb3_unicode_ci']];
+        yield [['collation' => 'utf8mb3_unicode_ci'], ['collation' => 'utf8mb3_unicode_ci']];
+        yield [['collation' => 'utf8mb3_unicode_ci'], ['collation' => 'utf8_unicode_ci']];
+        yield [
+            ['charset' => 'utf8', 'collation' => 'utf8_unicode_ci'],
+            ['charset' => 'utf8', 'collation' => 'utf8_unicode_ci'],
+        ];
+
+        yield [
+            ['charset' => 'utf8', 'collation' => 'utf8_unicode_ci'],
+            ['charset' => 'utf8mb3', 'collation' => 'utf8mb3_unicode_ci'],
+        ];
+
+        yield [
+            ['charset' => 'utf8mb3', 'collation' => 'utf8mb3_unicode_ci'],
+            ['charset' => 'utf8', 'collation' => 'utf8_unicode_ci'],
+        ];
+
+        yield [
+            ['charset' => 'utf8mb3', 'collation' => 'utf8mb3_unicode_ci'],
+            ['charset' => 'utf8mb3', 'collation' => 'utf8mb3_unicode_ci'],
+        ];
+    }
+
+    /**
+     * @param array<string,string> $options1
+     * @param array<string,string> $options2
+     */
+    #[DataProvider('equivalentCharsetAndCollationProvider')]
+    public function testThereAreNoRedundantAlterTableStatements(array $options1, array $options2): void
+    {
+        $column1 = new Column('bar', new StringType(), ['length' => 32, 'platformOptions' => $options1]);
+        $table1  = new Table(name: 'foo6146', columns: [$column1]);
+
+        $column2 = new Column('bar', new StringType(), ['length' => 32, 'platformOptions' => $options2]);
+        $table2  = new Table(name: 'foo6146', columns: [$column2]);
+
+        $this->dropAndCreateTable($table1);
+
+        $schemaManager = $this->connection->createSchemaManager();
+        $oldSchema     = $schemaManager->introspectSchema();
+        $newSchema     = new Schema([$table2]);
+        $comparator    = $schemaManager->createComparator();
+        $schemaDiff    = $comparator->compareSchemas($oldSchema, $newSchema);
+        $alteredTables = $schemaDiff->getAlteredTables();
+
+        self::assertEmpty($alteredTables);
+    }
+}