如何在單元測試時模擬db失敗

Question

我使用phpUnit並通過擴展PHPUnit_Extensions_Database_TestCase來編寫涉及數據庫的測試。 如何模擬數據庫故障以測試我的錯誤檢查？我應該測試什麼樣的失敗發生，除了數據庫被關閉？

我發現this Ruby on Rails question，但發現它與phpUnit無關。

Answer 1

我把代碼塊分開，然後use Mocks/Stubs in PHPUnit去控制從數據庫調用返回來包含錯誤，所以我的主代碼會處理這個錯誤。我不使用實際的數據庫，而是測試執行交互的代碼，以通過例外或您的代碼期望的方法來處理數據庫錯誤。

爲了模擬從您的代碼與模擬相同的回報，你會做以下幾點：使用

$stub = $this->getMock('YourDBClass'); 

// Configure the stub to return an error when the RunQuery method is called 
$stub->expects($this->any()) 
    ->method('RunQuery') 
    ->will($this->throwException(new SpecificException)); 

您可以測試的@expectsException

/** 
* @expectedException SpecificException 
*/ 
public function testDBError() 
{ 
    $stub = $this->getMock('YourDBClass'); 

    // Configure the stub to return an error when the RunQuery method is called 
    $stub->expects($this->any()) 
     ->method('RunQuery') 
     ->will($this->throwException(new SpecificException)); 

    $stub->RunQuery(); 
} 

或使用setExpectedException

public function testDBError() 
{ 
    $stub = $this->getMock('YourDBClass'); 

    // Configure the stub to return an error when the RunQuery method is called 
    $stub->expects($this->any()) 
     ->method('RunQuery') 
     ->will($this->throwException(new SpecificException)); 

    $this->setExpectedException('SpecificException'); 
    $stub->RunQuery(); 
} 

然後您將以相同的方式測試已知回報

public function testDBQueryReturns1() 
{ 
    $stub = $this->getMock('YourDBClass'); 

    // Configure the stub to return an error when the RunQuery method is called 
    $stub->expects($this->any()) 
     ->method('RunQuery') 
     ->will($this->returnValue(1)); 

    $this->assertEquals(1, $stub->RunQuery(), 'Testing for the proper return value'); 
}