public function testUpdate()
 {
     $obj = new Book($this->conn);
     $obj->id = 1;
     $obj->name = 'foo';
     $obj->description = 'bar';
     $this->conn->expects($this->once())->method('update')->with('books', ['id' => 1, 'name' => 'foo', 'description' => 'bar'], ['id' => 1]);
     $this->assertFalse($obj->isStored());
     $obj->update();
     $this->assertTrue($obj->isStored());
 }