public function testSetExpression()
 {
     $this->assertEquals("{'test':'myval','test2':2}", CqlAssembler::stringify(MapExpression::create(['test' => 'myval', 'test2' => 2])));
     $this->assertEquals("\"testfield\" + {'test'}", CqlAssembler::stringify(AdditionExpression::create(FieldExpression::create('testfield'), SetExpression::create('test'))));
 }