How do I get PHPUnit to substitute a class in my test method?

I have a class I want to test. Here is the code:开发者_运维知识库

class MyClass
{
    function functionToTest() {

        $class = new Example();

}

In PHPUnit, can I use mocks/stubs to substitute for the Example class?

In my test method:

class MyClassTest extends PHPUnit_Framework_TestCase {

    function testFunctionTest() {
        $testClass = new MyClass();
        $result = $testClass->functionTest();

    }

}

So instead of using the actual "Example" class, can PHPUnit intervene here and use the mock to represent "new Example()" ?

The best solution would be to inject an Example instance into functionToTest() method:

function functionToTest( Example $class )

Then you'll be able to mock it in your unit tests:

function testFunctionTest() {
    $testClass = new MyClass();
    $class = $this->getMock( 'Example' );
    $result = $testClass->functionTest( $class );

}

But if this approach is for some reason not an option for you, try using set_new_overload() function provided by the test_helpers extensions. See more info in Sebastian Bergmann's blog.