public function testDropForeignKey()
 {
     $refTable = new \Phinx\Db\Table('ref_table', array(), $this->adapter);
     $refTable->addColumn('field1', 'string')->save();
     $table = new \Phinx\Db\Table('table', array(), $this->adapter);
     $table->addColumn('ref_table_id', 'integer')->save();
     $fk = new \Phinx\Db\Table\ForeignKey();
     $fk->setReferencedTable($refTable)->setColumns(array('ref_table_id'))->setReferencedColumns(array('id'));
     $this->adapter->addForeignKey($table, $fk);
     $this->assertTrue($this->adapter->hasForeignKey($table->getName(), array('ref_table_id')));
     $this->adapter->dropForeignKey($table->getName(), array('ref_table_id'));
     $this->assertFalse($this->adapter->hasForeignKey($table->getName(), array('ref_table_id')));
 }