php - 支持链接方法的模拟对象

Question

我想知道是否有一种相当简洁的方法来模拟支持方法链的对象...例如，数据库查询对象可能有一个如下所示的方法调用:

$result = $database->select('my_table')->where(array('my_field'=>'a_value'))->limit(1)->execute();

如果我必须模拟两个不同的选择查询以便它们返回不同的结果，问题就来了。有什么想法吗？

这是专门针对 PHPUnit 的，但其他单元测试框架的经验会有所帮助。

Answer 1

我不确定这是你要找的，所以请发表评论:

class StubTest extends PHPUnit_Framework_TestCase
{
    public function testChainingStub()
    {
        // Creating the stub with the methods to be called
        $stub = $this->getMock('Zend_Db_Select', array(
            'select', 'where', 'limit', 'execute'
        ), array(), '', FALSE);

        // telling the stub to return a certain result on execute
        $stub->expects($this->any())
             ->method('execute')
             ->will($this->returnValue('expected result'));

        // telling the stub to return itself on any other calls
        $stub->expects($this->any())
             ->method($this->anything())
             ->will($this->returnValue($stub));

        // testing that we can chain the stub
        $this->assertSame(
            'expected result',
            $stub->select('my_table')
                 ->where(array('my_field'=>'a_value'))
                 ->limit(1)
                 ->execute()
        );
    }
}

您可以将其与期望相结合:

class StubTest extends PHPUnit_Framework_TestCase
{
    public function testChainingStub()
    {
        // Creating the stub with the methods to be called
        $stub = $this->getMock('Zend_Db_Select', array(
            'select', 'where', 'limit', 'execute'
        ), array(), '', FALSE);

        // overwriting stub to return something when execute is called
        $stub->expects($this->exactly(1))
             ->method('execute')
             ->will($this->returnValue('expected result'));

        $stub->expects($this->exactly(1))
             ->method('limit')
             ->with($this->equalTo(1))
             ->will($this->returnValue($stub));

        $stub->expects($this->exactly(1))
             ->method('where')
             ->with($this->equalTo(array('my_field'=>'a_value')))
             ->will($this->returnValue($stub));

        $stub->expects($this->exactly(1))
             ->method('select')
             ->with($this->equalTo('my_table'))
             ->will($this->returnValue($stub));

        // testing that we can chain the stub
        $this->assertSame(
            'expected result',
            $stub->select('my_table')
                 ->where(array('my_field'=>'a_value'))
                 ->limit(1)
                 ->execute()
        );
    }
}