如何使用PHPUnit模拟实现Iterator接口的类？

Question

如何Iterator以强大的方式模拟实现接口的类的依赖项？

Answer 1

已经有几个现有的解决方案已经解决了这个问题,但我见过的所有解决方案都有类似的弱点:他们依赖->expects($this->at(n)).PHPUnit中的'expected at'函数有一些奇怪的行为,因为计数器用于模拟的每个方法调用.这意味着如果您在直接foreach之外对迭代器进行方法调用,则必须调整迭代器模拟.

解决方法是创建一个包含基本迭代器数据(源数组和位置)的对象,并将其传递给returnCallback闭包.因为它是通过引用传递的,所以对象在调用之间保持最新,所以我们可以模拟每个方法来模拟一个简单的迭代器.现在我们可以正常使用迭代器模拟,而不必担心严格的调用顺序.

下面的示例方法,您可以使用它来设置迭代器模拟:

/**
 * Setup methods required to mock an iterator
 *
 * @param PHPUnit_Framework_MockObject_MockObject $iteratorMock The mock to attach the iterator methods to
 * @param array $items The mock data we're going to use with the iterator
 * @return PHPUnit_Framework_MockObject_MockObject The iterator mock
 */
public function mockIterator(PHPUnit_Framework_MockObject_MockObject $iteratorMock, array $items)
{
    $iteratorData = new \stdClass();
    $iteratorData->array = $items;
    $iteratorData->position = 0;

    $iteratorMock->expects($this->any())
                 ->method('rewind')
                 ->will(
                     $this->returnCallback(
                         function() use ($iteratorData) {
                             $iteratorData->position = 0;
                         }
                     )
                 );

    $iteratorMock->expects($this->any())
                 ->method('current')
                 ->will(
                     $this->returnCallback(
                         function() use ($iteratorData) {
                             return $iteratorData->array[$iteratorData->position];
                         }
                     )
                 );

    $iteratorMock->expects($this->any())
                 ->method('key')
                 ->will(
                     $this->returnCallback(
                         function() use ($iteratorData) {
                             return $iteratorData->position;
                         }
                     )
                 );

    $iteratorMock->expects($this->any())
                 ->method('next')
                 ->will(
                     $this->returnCallback(
                         function() use ($iteratorData) {
                             $iteratorData->position++;
                         }
                     )
                 );

    $iteratorMock->expects($this->any())
                 ->method('valid')
                 ->will(
                     $this->returnCallback(
                         function() use ($iteratorData) {
                             return isset($iteratorData->array[$iteratorData->position]);
                         }
                     )
                 );

    $iteratorMock->expects($this->any())
                 ->method('count')
                 ->will(
                     $this->returnCallback(
                         function() use ($iteratorData) {
                             return sizeof($iteratorData->array);
                         }
                     )
                 );

    return $iteratorMock;
}

Answer 2

这是一个结合了两全其美的解决方案，使用ArrayIterator内部：

具有phpunit/phpunit模拟设施

/**
 * @return \PHPUnit_Framework_MockObject_MockObject|SomeIterator
 */
private function createSomeIteratorDouble(array $items = []): SomeIterator
{
    $someIterator = $this->createMock(SomeIterator::class);

    $iterator = new \ArrayIterator($items);

    $someIterator
        ->method('rewind')
        ->willReturnCallback(function () use ($iterator): void {
            $iterator->rewind();
        });

    $someIterator
        ->method('current')
        ->willReturnCallback(function () use ($iterator) {
            return $iterator->current();
        });

    $someIterator
        ->method('key')
        ->willReturnCallback(function () use ($iterator) {
            return $iterator->key();
        });

    $someIterator
        ->method('next')
        ->willReturnCallback(function () use ($iterator): void {
            $iterator->next();
        });

    $someIterator
        ->method('valid')
        ->willReturnCallback(function () use ($iterator): bool {
            return $iterator->valid();
        });

    return $someIterator;
}

和phpspec/prophecy

/**
 * @return \PHPUnit_Framework_MockObject_MockObject|SomeIterator
 */
private function createSomeIteratorDouble(array $items = []): SomeIterator
{
    $someIterator = $this->prophesize(\ArrayIterator::class);

    $iterator = new \ArrayIterator($items);

    $someIterator
        ->rewind()
        ->will(function () use ($iterator): void {
            $iterator->rewind();
        });

    $someIterator
        ->current()
        ->will(function () use ($iterator) {
            return $iterator->current();
        });

    $someIterator
        ->key()
        ->will(function () use ($iterator) {
            return $iterator->key();
        });

    $someIterator
        ->next()
        ->will(function () use ($iterator): void {
            $iterator->next();
        });

    $someIterator
        ->valid()
        ->will(function () use ($iterator): bool {
            return $iterator->valid();
        });

    return $someIterator->reveal();
}

Answer 3

如果你只需要针对泛型迭代器进行测试,那么PHP(在SPL扩展中 - 在PHP> 5.3中无法关闭)内置了数组包装器,它们实现了Iterable:SPL Iterators.例如

$mock_iterator = new \ArrayIterator($items);
$test_class->methodExpectingGenericIterator($mock_iterator);
$resulting_data = $mock_iterator->getArrayCopy();