如何测试PHP PDO Singleton类？

Question

PHP PDO Singleton Class:

<?php 

require_once('app/config.php'); // Require constants HOST, DATABASE, USER, PASSWORD 

/* 

dbConnection class. 

Manages connections to and operations on the database. Call dbConnection::getInstance() to return an instance. 
Prepare your statements by calling prepareQuery() on the object 

Attribute list: 

$instance: 
> Static self instance to manage database resource 

$connection: 
> Holds connection resource 

$sth: 
> Statement handler variable. Handles SQL statements. 
_______________________________________________________________________________________________________________ 

Method list: 

getInstance(): 
> Creates or returns existing connection to the database 

prepareQuery(): 
> Prepares the $sth variable for execution. 

bindParameter(): 
> Binds parameters to the $sth variable. 

numRows($query): 
> Returns the number of returned from a query 

runQuery(): 
> Executes the current statement on the database 

fetchRow(): 
> Executes the current statement then returns an associative array 

fetchObj($className, $parameters = NULL): 
> Executes the current statement and returns an object of your specification. Also takes additional parameters to pass to the object's constructor. 


*/ 

class dbConnection 
{ 
    private static $instance = NULL; 
    private $connection; 
    private $sth; 

    function __construct() 
    { 
     $this->connection = new PDO('mysql:host=' . HOST . ';dbname=' . DATABASE, USER, PASSWORD); 
    } 

    function getInstance() 
    { 
     if (self::$instance == NULL) 
      self::$instance = new dbConnection(); 
     return self::$instance; 
    } 

    function prepareQuery($query) 
    { 
     $this->sth = $this->connection->prepare($query); 
    } 

    function bindParameter($number, $value) 
    { 
     $this->sth->bindParam($number, $value); 
    } 

    function numRows() 
    { 
     try 
     { 
      $this->sth->execute(); 

      $count = $this->sth->rowCount(); 
      return $count; 
     } 
     catch(PDOException $e) 
     { 
      echo __LINE__.$e->getMessage(); 
     } 
    } 

    function runQuery() 
    { 
     try 
     { 
      $this->sth->execute() or print_r($connection->errorInfo()); 
     } 
     catch(PDOException $e) 
     { 
      echo __LINE__.$e->getMessage(); 
     } 
    } 

    function fetchRow() 
    { 
     try 
     { 
      $this->sth->setFetchMode(PDO::FETCH_ASSOC); 
      $this->sth->execute(); 
      return $this->sth; 
     } 
     catch(PDOException $e) 
     { 
      echo __LINE__.$e->getMessage(); 
     } 
    } 

    function fetchObj($className, $parameters = NULL) 
    { 
     try 
     { 
      $this->sth->setFetchMode(PDO::FETCH_CLASS, $className, $parameters); 
      $this->sth->execute(); 
      return $this->sth; 
     } 
     catch(PDOException $e) 
     { 
      echo __LINE__.$e->getMessage(); 
     } 
    } 
} 
?> 

如何测试单？ 每次取一个对象，当你在对象结束时关闭对象。

Answer 1

I think you are misapplying the Singleton pattern here.

然而，测试单身是可能的。引用Testing Code that uses Singletons

PHPUnit具有用于类的静态属性的备份/恢复机制。

这是PHPUnit的另一个特性，它使得使用全局状态（包括但不限于全局和超全局变量以及类的静态属性）的代码更容易测试。

另见http://www.phpunit.de/manual/current/en/fixtures.html#fixtures.global-state

的@backupStaticAttributes注释，则在section called “@backupStaticAttributes”讨论可以用来控制备份和恢复操作的静态属性。另外，您也可以提供要从备份中排除的静态属性的黑名单和恢复操作这样

所以，如果你想禁用的备份，你会做

class MyPdoTest extends PHPUnit_Framework_TestCase 
{ 
    protected $backupStaticAttributesBlacklist = array(
     'dbConnection' => array('instance') 
    );  

    // more test code 
} 

而且看看Database Testing

Answer 2

单身人士是坏消息，因为我已经解释了here。

更具体到你的问题，单身人士是非常困难的单元测试。这是他们是坏消息的原因之一。

改为使用dependency-injection。

编辑补充：

我想每个单元测试是在自己的测试套件，所有的测试套件被设置为在一个单独的进程中运行，你可以写一组单元测试。这应该将每个单元测试与其他测试隔离开来。

虽然性能会很糟糕，但您最好使用DI方法代替。

（我假设你正在使用phpunit为单元测试这里）