{

private function makeObj(string $table, string $name, $diff = null): object

{

return (object) [

'table' => $table,

'name' => $name,

'diff' => $diff,

];

}

// ── Bug #17: MySQL DROP FOREIGN KEY syntax ─────────────────────────────

public function testMySQLDropForeignKeyUsesCorrectSyntax(): void

{

$fkDef = 'CONSTRAINT `fk_orders_user_id` FOREIGN KEY (`user_id`) REFERENCES `users`(`id`)';

$diffOp = new \Diff\DiffOp\DiffOpRemove($fkDef);

$obj = $this->makeObj('orders', 'fk_orders_user_id', $diffOp);

$sql = new AlterTableDropConstraintSQL($obj, new MySQLDialect());

$this->assertSame(

'ALTER TABLE `orders` DROP FOREIGN KEY `fk_orders_user_id`;',

$sql->getUp()

);

}

public function testMySQLDropNonFKConstraintUsesDropConstraint(): void

{

$checkDef = 'CONSTRAINT `chk_age` CHECK (`age` > 0)';

$diffOp = new \Diff\DiffOp\DiffOpRemove($checkDef);

$obj = $this->makeObj('users', 'chk_age', $diffOp);

$sql = new AlterTableDropConstraintSQL($obj, new MySQLDialect());

$this->assertSame(

'ALTER TABLE `users` DROP CONSTRAINT `chk_age`;',

$sql->getUp()

);

}

public function testPostgresDropFKUsesStandardSyntax(): void

{

$fkDef = 'CONSTRAINT "fk_orders_user_id" FOREIGN KEY ("user_id") REFERENCES "users"("id")';

$diffOp = new \Diff\DiffOp\DiffOpRemove($fkDef);

$obj = $this->makeObj('orders', 'fk_orders_user_id', $diffOp);

$sql = new AlterTableDropConstraintSQL($obj, new PostgresDialect());

$this->assertSame(

'ALTER TABLE "orders" DROP CONSTRAINT "fk_orders_user_id";',

$sql->getUp()

);

}

public function testSQLiteDropFKUsesStandardSyntax(): void

{

$fkDef = 'CONSTRAINT "fk_orders_0" FOREIGN KEY ("user_id") REFERENCES "users" ("id")';

$diffOp = new \Diff\DiffOp\DiffOpRemove($fkDef);

$obj = $this->makeObj('orders', 'fk_orders_0', $diffOp);

$sql = new AlterTableDropConstraintSQL($obj, new SQLiteDialect());

$this->assertSame(

'ALTER TABLE "orders" DROP CONSTRAINT "fk_orders_0";',

$sql->getUp()

);

}

// ── getDown restores constraint ────────────────────────────────────────

public function testGetDownRestoresConstraint(): void

{

$constraint = 'CONSTRAINT `fk_orders_user_id` FOREIGN KEY (`user_id`) REFERENCES `users`(`id`)';

$diffOp = new \Diff\DiffOp\DiffOpRemove($constraint);

$obj = $this->makeObj('orders', 'fk_orders_user_id', $diffOp);

$sql = new AlterTableDropConstraintSQL($obj, new MySQLDialect());

$this->assertSame(

"ALTER TABLE `orders` ADD $constraint;",

$sql->getDown()

);

}

// ── Empty / null name validation ───────────────────────────────────────

public function testGetUpThrowsOnEmptyName(): void

{

$diffOp = new \Diff\DiffOp\DiffOpRemove('FOREIGN KEY (`col`) REFERENCES `other`(`id`)');

$obj = $this->makeObj('orders', '', $diffOp);

$sql = new AlterTableDropConstraintSQL($obj, new MySQLDialect());

$this->expectException(InvalidConstraintException::class);

$this->expectExceptionMessage('constraint name is empty');

$sql->getUp();

}

public function testGetUpThrowsOnNullName(): void

{

$diffOp = new \Diff\DiffOp\DiffOpRemove('FOREIGN KEY (`col`) REFERENCES `other`(`id`)');

$obj = (object) [

'table' => 'orders',

'name' => null,

'diff' => $diffOp,

];

$sql = new AlterTableDropConstraintSQL($obj, new MySQLDialect());

$this->expectException(InvalidConstraintException::class);

$sql->getUp();

}

// ── AlterTableAddConstraintSQL: getDown uses dialect ───────────────────

public function testAddConstraintDownMySQLDropsForeignKey(): void

{

$fkDef = 'CONSTRAINT `fk_posts_user` FOREIGN KEY (`user_id`) REFERENCES `users`(`id`)';

$diffOp = new \Diff\DiffOp\DiffOpAdd($fkDef);

$obj = $this->makeObj('posts', 'fk_posts_user', $diffOp);

$sql = new AlterTableAddConstraintSQL($obj, new MySQLDialect());

$this->assertSame(

'ALTER TABLE `posts` DROP FOREIGN KEY `fk_posts_user`;',

$sql->getDown()

);

}

public function testAddConstraintDownPostgresUsesDropConstraint(): void

{

$fkDef = 'CONSTRAINT "fk_posts_user" FOREIGN KEY ("user_id") REFERENCES "users"("id")';

$diffOp = new \Diff\DiffOp\DiffOpAdd($fkDef);

$obj = $this->makeObj('posts', 'fk_posts_user', $diffOp);

$sql = new AlterTableAddConstraintSQL($obj, new PostgresDialect());

$this->assertSame(

'ALTER TABLE "posts" DROP CONSTRAINT "fk_posts_user";',

$sql->getDown()

);

}

// ── AlterTableChangeConstraintSQL ──────────────────────────────────────

public function testChangeConstraintMySQLUsesForeignKeyDrop(): void

{

$oldDef = 'CONSTRAINT `fk_orders_user` FOREIGN KEY (`user_id`) REFERENCES `users`(`id`)';

$newDef = 'CONSTRAINT `fk_orders_user` FOREIGN KEY (`user_id`) REFERENCES `users`(`id`) ON DELETE CASCADE';

$diffOp = new \Diff\DiffOp\DiffOpChange($oldDef, $newDef);

$obj = $this->makeObj('orders', 'fk_orders_user', $diffOp);

$sql = new AlterTableChangeConstraintSQL($obj, new MySQLDialect());

$this->assertSame(

"ALTER TABLE `orders` DROP FOREIGN KEY `fk_orders_user`;\nALTER TABLE `orders` ADD $newDef;",

$sql->getUp()

);

$this->assertSame(

"ALTER TABLE `orders` DROP FOREIGN KEY `fk_orders_user`;\nALTER TABLE `orders` ADD $oldDef;",

$sql->getDown()

);

}

public function testChangeConstraintPostgresUsesDropConstraint(): void

{

$oldDef = 'CONSTRAINT "fk_orders_user" FOREIGN KEY ("user_id") REFERENCES "users"("id")';

$newDef = 'CONSTRAINT "fk_orders_user" FOREIGN KEY ("user_id") REFERENCES "users"("id") ON DELETE CASCADE';

$diffOp = new \Diff\DiffOp\DiffOpChange($oldDef, $newDef);

$obj = $this->makeObj('orders', 'fk_orders_user', $diffOp);

$sql = new AlterTableChangeConstraintSQL($obj, new PostgresDialect());

$this->assertSame(

"ALTER TABLE \"orders\" DROP CONSTRAINT \"fk_orders_user\";\nALTER TABLE \"orders\" ADD $newDef;",

$sql->getUp()

);

}