简述

上篇文章讨论了如何利用命名空间实现对PHP内建函数的mocking,本文介绍另一种实现方法——依赖注入。

出于编写可测试代码的需要,依赖注入是经常使用的一种技术。通过把代码中依赖的其它数据获取服务提取出来、和原有逻辑解耦,提高代码的可测试性。只需mock这些依赖并注入到测试对象中即可。

实现

对原有代码的重构

先把原有代码用依赖注入的方式重构(为突出重点,省略了和上篇文章中重复的部分):

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// ...

use Ox3f\LaravelUtils\Services\Builtins;

/**
* Class Log
* @author donie
*/
class Log
{
// ...

private $builtins; // Builtin functions

private function __construct() {
$this->builtins = new Builtins();

// ...
}

// ...

public static function inject($key, $service)
{
self::getInstance()->$key = $service;
}

/**
* Parse the call stack
*
* @return void
*/
private function parseCallStack() {
$traceInfo = $this->builtins->debug_backtrace(DEBUG_BACKTRACE_PROVIDE_OBJECT|DEBUG_BACKTRACE_IGNORE_ARGS, 5);

// ...

}

// ...

}

Builtins类的实现:

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<?php
namespace Ox3f\LaravelUtils\Services;

/**
* Class Builtins
* @author donie
*/
class Builtins
{
public function debug_backtrace()
{
return call_user_func_array('debug_backtrace', func_get_args());
}

}

debug_backtrace()封装进了Builtins类,并在测试对象中通过这个类调用内建函数。inject()用于注入依赖,这样可以在测试类中把mock注入到测试对象中。

测试类的实现

代码如下:

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<?php
use PHPUnit\Framework\TestCase;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Facades\Request;
use Illuminate\Support\Facades\Log as LaravelLog;
use Ox3f\LaravelUtils\Log\Log;
use \Mockery as m;

class LogTest extends TestCase
{
public function setUp()
{
Auth::shouldReceive('user')
->once()
->andReturn((object)['name' => 'jim',]);
}

public function tearDown()
{
m::close();
}

/**
* @covers Ox3f\LaravelUtils\Log\Log::saveInput
* @covers Ox3f\LaravelUtils\Log\Log::saveOutput
* @covers Ox3f\LaravelUtils\Log\Log::parseCallStack
* @covers Ox3f\LaravelUtils\Log\Log::getInstance
* @covers Ox3f\LaravelUtils\Log\Log::__construct
* @covers Ox3f\LaravelUtils\Log\Log::__callStatic
*/
public function testAll()
{
$mock = m::mock('Ox3f\LaravelUtils\Services\Builtins');
$mock->shouldReceive('debug_backtrace')
->andReturnUsing(function() use ($mock) {
if ($mock->calledInController) {
return json_decode('[{"file":"\/Users\/xbot\/Sites\/sample-project\/vendor\/xbot\/laravel-utils\/src\/Log\/Log.php","line":85,"function":"parseCallStack","class":"Ox3f\\\LaravelUtils\\\Log\\\Log","object":{},"type":"->"},{"file":"\/Users\/xbot\/Sites\/sample-project\/app\/Api\/V1\/Controllers\/WorkController.php","line":29,"function":"saveInput","class":"Ox3f\\\LaravelUtils\\\Log\\\Log","type":"::"},{"function":"save","class":"App\\\Api\\\V1\\\Controllers\\\WorkController","object":{},"type":"->"},{"file":"\/Users\/xbot\/Sites\/sample-project\/vendor\/laravel\/framework\/src\/Illuminate\/Routing\/Controller.php","line":55,"function":"call_user_func_array"},{"file":"\/Users\/xbot\/Sites\/sample-project\/vendor\/laravel\/framework\/src\/Illuminate\/Routing\/ControllerDispatcher.php","line":44,"function":"callAction","class":"Illuminate\\\Routing\\\Controller","object":{},"type":"->"}]', true);
} else {
return json_decode('[{"file":"\/Users\/xbot\/Sites\/sample-project\/vendor\/xbot\/laravel-utils\/src\/Log\/Log.php","line":85,"function":"parseCallStack","class":"Ox3f\\\LaravelUtils\\\Log\\\Log","object":{},"type":"->"},{"file":"\/Users\/xbot\/Sites\/sample-project\/app\/Notation.php","line":21,"function":"saveInput","class":"Ox3f\\\LaravelUtils\\\Log\\\Log","type":"::"},{"file":"\/Users\/xbot\/Sites\/sample-project\/app\/Api\/V1\/Controllers\/NotationController.php","line":32,"function":"incrNo","class":"App\\\Notation","type":"::"},{"function":"save","class":"App\\\Api\\\V1\\\Controllers\\\NotationController","object":{},"type":"->"},{"file":"\/Users\/xbot\/Sites\/sample-project\/vendor\/laravel\/framework\/src\/Illuminate\/Routing\/Controller.php","line":55,"function":"call_user_func_array"}]', true);
}
});
Log::inject('builtins', $mock);

// test being called in a plain method
$mock->calledInController = false;
LaravelLog::shouldReceive('debug')
->once()
->with('jim | App\Notation::incrNo | Input:1');

Log::saveInput(1);

LaravelLog::shouldReceive('debug')
->once()
->with('jim | App\Notation::incrNo | Output:2');

Log::saveOutput(2);

// test being called in a controller action
$mock->calledInController = true;
Request::shouldReceive('path')
->once()
->andReturn('api/user');
Request::shouldReceive('except')
->once()
->with('_url')
->andReturn(['id' => 18,]);
LaravelLog::shouldReceive('debug')
->once()
->with('jim | api/user | Input:{"id":18}');

Log::saveInput();

Request::shouldReceive('path')
->once()
->andReturn('api/user');
LaravelLog::shouldReceive('debug')
->once()
->with('jim | api/user | Output:2');

Log::saveOutput(2);

Request::shouldReceive('path')
->once()
->andReturn('api/user');
LaravelLog::shouldReceive('error')
->once()
->with('jim | api/user | this is an error');

Log::error('this is an error');

$this->assertEquals(0, 0);
}
}

Builtins是个普通类,很容易mock。