php - 用具体值模拟 atLeastOnce，其余的不重要

Question

问题在 PHP 中，但适用于使用 xUnit 框架的任何语言。

我想要一个 mock，需要 140 次调用 jump 方法。
我需要验证，至少一次有一个以 500 作为参数的调用。
我不在乎是否所有调用都是 500，但我至少需要一个调用了 500 的调用。

$mock = $this->getMock('Trampoline', ['jump']);

$mock->expects($this->atLeastOnce())
     ->method('jump')
     ->with($this->equalTo(500))
     ->will($this->returnValue(true));

$sportsman->setTramploine($mock);
$sportsman->jumpToRandomHeights($times = 140); // this calls Trampoline->jump
// I need to verify the sportsman had jumped 
// to the height of 500 at least once out of the 140 jumps he is performing

在当前代码中，测试在第一次调用 jump 后失败，因为第一次调用的值不同于 500，这意味着 atLestOnce 这里只是表示应该调用该方法，而不是在其他调用中以特定值调用它。

---

解决方案

缺少的信息是在 with 中使用回调。感谢 edorian 在下面的回答，结果是这样的:

$testPassed = false;

$checkMinHeight = function ($arg) use(&$testPassed)
{
    if($arg === 500)
        $testPassed = true;

    // return true for the mock object to consider the input valid
    return true;
}


$mock = $this->getMock('Trampoline', ['jump'])
    ->expects($this->atLeastOnce())
    ->method('jump')
    ->with($checkMinHeight)
    ->will($this->returnValue(true));

$sportsman->setTramploine($mock);
$sportsman->jumpToRandomHeights($times = 1000); // this calls Trampoline->jump
// I need to verify the sportsman had jumped 
// to the height of 500 at least once out of the 1000 jumps he is performing


$this->assertTrue($testPassed, "Sportsman was expected to 
    jump 500m at least once");

Answer 1

你可以，但我能想到的使用 PHPUnits 模拟 API 的最佳实现看起来仍然很令人毛骨悚然。

另一种更易读的解决方法是创建您自己的 Trampoline 子类并在那里实现它。

但对于挑战:

假设这个类:

<?php
class FancyMocking {
    function doThing($value) { }
}

并且我们有 $x 调用，其中一个必须有 $value > 200:

---

<?php

class FancyMockingTest extends PHPUnit_Framework_TestCase {

    public function testAtLeastOfMy200CallsShouldHaveAValueGreaterThan500() {
      $maxInvocations = 200;

      $mock = $this->getMock('FancyMocking');
      $mock->expects($this->exactly($maxInvocations))
        ->method('doThing')
        ->with($this->callback(function ($value) use ($maxInvocations) { 
            static $invocationCount = 0;
            static $maxValue = 0;

            $maxValue = max($value, $maxValue);
            /* The assertion function will be called twice by PHPUnit due to implementation details, so the *2 is a hack for now */
            if (++$invocationCount == $maxInvocations * 2) { 
                $this->assertGreaterThan(200, $maxValue, 'in 500 tries the max value didn\'t to over 200');
            } 
            return true;
        }))
        ->will($this->returnCallback(function ($value) { 
            return $value >= 200;
        }));
     for($i = $maxInvocations - 2; $i; --$i) { 
          $mock->doThing(50);
     } 
     var_dump($mock->doThing(250));
     var_dump($mock->doThing(50));
    }


}

这将产生:

PHPUnit 3.7.9 by Sebastian Bergmann.

.bool(true)
bool(false)


Time: 0 seconds, Memory: 2.75Mb

OK (1 test, 2 assertions)

意味着 250 的调用返回 true 并且整个测试用例有效。

如果失败:

为了让它失败，我们将 var_dump($mock->doThing(250)); 更改为 var_dump($mock->doThing(70)); 并运行再次:

PHPUnit 3.7.9 by Sebastian Bergmann.

Fbool(false)


Time: 0 seconds, Memory: 2.75Mb

There was 1 failure:

1) FancyMockingTest::testAtLeastOfMy200CallsShouldHaveAValueGreaterThan500
Expectation failed for method name is equal to <string:doThing> when invoked 200 time(s)
in 500 tries the max value didn't to over 200
Failed asserting that 70 is greater than 200.

.../FancyMockingTest.php:29

FAILURES!
Tests: 1, Assertions: 1, Failures: 1.

---

不使用 PHPUnits 模拟 API 的解决方案类似于

class FancyMockingFakeImplementation extends FancyMocking，使用它代替模拟并在那里编写自定义逻辑。