I am trying to write a test for some very old code we have using PHPUnit. I've given the rough structure of it here, I am trying to test the isMember() method of ClassB which it inherits from ClassA. It should just be checking if a constant value exists in the class.
The problem I am having is that it is obviously a protected constructor, so I don't know how to test this as I keep getting protected contruct errors in PHPUnit as obviously the constructor is protected. Please advise how I test this?
abstract class ClassA implements InterfaceA {
private $mValueList;
protected static $instance;
protected function __construct() {
}
protected static function getInstance(ClassA $obj) {
if (is_null($obj->instance)) {
$obj->instance = $obj;
}
return $obj->instance;
}
public function isMember($value) {
return isset($this->mValueList[$value]);
}
....more methods......
}
class ClassB extends ClassA {
public static function getInstance() {
return parent::getInstance(new self());
}
const CON1 = 'string1';
const CON2 = 'string2';
}
You would test it like any other class, you just don't use the constructor in the test.
public function testIsMember() {
$classB = ClassB::getInstance();
$this->assertTrue($classB->isMember('string1'));
$this->assertFalse($classB->isMember('foo'));
}
I am making a guess on the assertions and you could refactor the test to use a data provider. But the general idea is the same. You don't invoke the constructor directly in your tests for a singleton. The getInstance method replaces the call to the constructor.
Related
I have a Factory Method to instance a class. Is there a way to prevent this class from direct instancing?
The only option I see is to use an argument passed into the __construct(), but that's not something I'm looking for.
On the other hand, making the __construct() private would be ideal, but I don't want MyClass to extend the Factory without actual need.
What do you guys think?
Factory Method:
class Factory
{
public static function instance()
{
return new MyClass(true);
}
}
MyClass:
class MyClass
{
public function __construct($isFactory = false)
{
if (!$isFactory) {
throw new Exception('Use Factory::instance() to create an object');
}
}
}
There are hacks to do that:
abusing inheritance to use a protected constructor
putting the factory method inside the class so that it can call the private constructor, which is actually not a hack. But then why not using the constructor in the first place?
using reflection to access the private constructor
I'm not promoting anything of that. What I personally do is documenting the API with things like #internal and leave it to the client following that contract.
In essence, your code should have read something like this:
THE FACTORY
<?php
class Factory {
public static function instance(){
return new MyClass(true); //HERE YOU ARE INSTANTIATING
}
}
THE CLASS TO BE INSTANTIATED VIA THE FACTORY
<?php
//NOT MyClass() <--- YOU ARE DEFINING.... NOT INSTANTIATING...
class MyClass {
public function __construct($isFactory = false) {
if (!$isFactory) {
throw new Exception('Use Factory::instance() to create an object');
}
}
//...MORE METHODS
}
Could you try this instead?
<?php
class Factory
{
private static $FACTORY_GUARANTOR; //ONLY SET DURING INSTANTIATION
public static function instance($type) {
if (class_exists($type)) {
self::$FACTORY_GUARANTOR = 1;
$instance = new $type();
self::$FACTORY_GUARANTOR = null;
return $instance;
}
else {
throw new Exception("Class not found...");
}
}
//YOU CAN GET $FACTORYGUARANTOR EXTERNALLY BUT NEVER SET IT;
public static function getGuarantor(){
return self::$FACTORY_GUARANTOR;
}
}
class MyClass {
protected $property1;
protected $property3;
protected $property2;
public function __construct() {
// IF SOMEONE TRIES TO INSTANTIATE THE CLASS OUTSIDE OF THE FACTORY... BLOW A WHISTLE
if(!Factory::getGuarantor()){
throw new Exception('Use Factory::instance() to create an object');
}
// IF THE PROGRAM MADE IT TO THIS POINT;
// JUST INSTANTIATE THE CLASS BECAUSE MOST LIKELY IT IS COMING FROM THE FACTORY
var_dump($this); // A LITTLE CONFIRMATION....
}
//...MORE METHODS
}
// TRY IT OUT:
/*INSTANCE A: RIGHT*/ $theClass = Factory::instance("MyClass"); //INSTANTIATES THE CLASS
/*INSTANCE B: WRONG*/ $theClass = new MyClass(); //THROWS AN EXCEPTION
The easiest way is to define your base class as abstract. The abstract classes cannot be directly instanced, so you will have to redefine their abstract members in the inherited classes:
abstract class Factory
{
abstract public function foo();
}
class InheritedClass extends Factory
{
public function foo()
{
// Do something
}
}
// $obj1 = new Factory(); // Will produce an error
$obj1 = new InheritedClass(); // Will be executed successfully
You can read more for the abstract classes here: PHP: Class Abstraction - Manual.
For me, the best way is to use ReflectionClass:
class MyClass
{
public const FRIEND_CLASSES = [Factory::class];
protected function __construct() {}
}
trait Constructor
{
protected function createObject(string $className, array $args = [])
{
if (!in_array(static::class, $className::FRIEND_CLASSES)) {
throw new \Exception("Call to private or protected {$className}::__construct() from invalid context");
}
$reflection = new ReflectionClass($className);
$constructor = $reflection->getConstructor();
$constructor->setAccessible(true);
$object = $reflection->newInstanceWithoutConstructor();
$constructor->invokeArgs($object, $args);
return $object;
}
}
class Factory
{
use Constructor;
public function MyClass(): MyClass
{
return $this->createObject(MyClass::class);
}
}
In constant FRIEND_CLASSES you can define in which classes the class can be instanced.
trait is used because this functionality can be used in different factories that are not related.
If you need to put parameters into constructor of the class, put them as second parameter of createObject.
Details I described in the article "Forbidding of creating objects outside factory in PHP"
I've already read Why does PHP 5.2+ disallow abstract static class methods? and How to force an implementation of a protected static function - the second is very similar to my case - but I am still without answer. Basically, I want to assure, that every child of my abstract class has implementation of protected static method, without implementing it as this has no meaning and because of lack of key informations there. Also, it must be static (because caller method is static and it has no context) and protected (so I cannot use interface, and I do not want anyone to call it directly), and it will be called by late static binding. Any ideas?
Dummy code below to illuminate my case:
abstract class BaseClass {
public static function foo() {
// some common stuff
static::bar();
// rest of common stuff
}
public function whoooaaa($condition) {
if ($condition) {
AClass::foo();
} else {
BClass::foo();
}
}
}
class AClass extends BaseClass {
protected static function bar() {
// do something
}
}
class BClass extends BaseClass {
protected static function bar() {
// do something else
}
}
// end somewhere else in my code, two constructions, both used:
AClass::foo();
// ....
$baseClassInheritedInstance->whoooaaa($variableCondition);
My only solution, ugly one, is to implement dummy protected static method in base class and throw a generic exception, so that it must be implemented by inheritance.
You can add a static factory that will fill context for casual objects.
class Factory() {
public static getObject($condition) {
$object = $condition ? new A() : new B();
// you can fill context here and/or use singleton/cache
return $object;
}
}
abstract class Base {
abstract function concreteMethod();
}
class A extends Base {...}
class B extends Base {...}
I'm writing a unit test for a class method that calls another class's method using a mock, only the method that needs to be called is declared as final, so PHPUnit is unable to mock it. Is there a different approach I can take?
example:
class to be mocked
class Class_To_Mock
{
final public function needsToBeCalled($options)
{
...
}
}
my test case
class MyTest extends PHPUnit_Framework_TestCase
{
public function testDoSomething()
{
$mock = $this->getMock('Class_To_Mock', array('needsToBeCalled'));
$mock->expects($this->once())
->method('needsToBeCalled')
->with($this->equalTo(array('option'));
}
}
Edit: If using the solution provided by Mike B and you have a setter/getter for the object you're mocking that does type checking (to ensure the correct object was passed into the setter), you'll need to mock the getter on the class you're testing and have it return the other mock.
example:
class to be mocked
class Class_To_Mock
{
final public function needsToBeCalled($options)
{
...
}
}
mock
class Class_To_MockMock
{
public function needsToBeCalled($options)
{
...
}
}
class to be tested
class Class_To_Be_Tested
{
public function setClassToMock(Class_To_Mock $classToMock)
{
...
}
public function getClassToMock()
{
...
}
public function doSomething()
{
$this->getClassToMock()
->needsToBeCalled(array('option'));
}
}
my test case
class MyTest extends PHPUnit_Framework_TestCase
{
public function testDoSomething()
{
$classToTest = $this->getMock('Class_To_Be_Tested', array('getClassToMock'));
$mock = $this->getMock('Class_To_MockMock', array('needsToBeCalled'));
$classToTest->expects($this->any())
->method('getClassToMock')
->will($this->returnValue($mock));
$mock->expects($this->once())
->method('needsToBeCalled')
->with($this->equalTo(array('option'));
$classToTest->doSomething();
}
}
I don't think PHPUnit supports stubbing/mocking of final methods. You may have to create your own stub for this situation and do some extension trickery:
class myTestClassMock {
public function needsToBeCalled() {
$foo = new Class_To_Mock();
$result = $foo->needsToBeCalled();
return array('option');
}
}
Found this in the PHPUnit Manual under Chapter 11. Test Doubles
Limitations
Please note that final, private and static methods cannot be stubbed or mocked. They are ignored by PHPUnit's test double functionality and retain their original behavior.
I just stumbled upon this issue today. Another alternative is to mock the interface that the class implements, given that it implements an interface and you use the interface as type hinting.
For example, given the problem in question, you can create an interface and use it as follows:
interface Interface_To_Mock
{
function needsToBeCalled($options);
}
class Class_To_Mock implements Interface_To_Mock
{
final public function needsToBeCalled($options)
{
...
}
}
class Class_To_Be_Tested
{
public function setClassToMock(Interface_To_Mock $classToMock)
{
...
}
...
}
class MyTest extends PHPUnit_Framework_TestCase
{
public function testDoSomething()
{
$mock = $this->getMock('Interface_To_Mock', array('needsToBeCalled'));
...
}
}
When creating a Singleton in PHP, I ensure that it cannot be instantiated by doing the following:
class Singleton {
private function __construct() {}
private function __clone() {}
public static function getInstance() {}
}
However, I realised that defining a class as 'abstract' means that it cannot be instantiated. So is there anything wrong with doing the following instead:
abstract class Singleton {
public static function getInstance() {}
}
The second scenario allows me to write fewer lines of code which would be nice. (Not that it actually makes much of a difference.)
When creating a singleton in PHP, declaring the __construct and __clone as private ensures that the class cannot be instanciated from the outside : it can still be instanciated from inside its declaration.
When declaring a class as abstract, it can not be instanciated at all ; not even from inside its declaration.
This means your solution would not work : in the second case, your getInstance() method will not be able to instanciate the class -- while it can do so in the first case.
No because then then you can't instantiate the class at all (not even in the static getInstance method). The private constructor in the singleton example just assures, that only the static getInstance method from the same class can access the constructor.
No, you cannot use an abstract class instead of a private __construct() when creating a singleton. But if your intention is to create an Abstract Singleton from which to extend from, you can do so like this:
abstract class Singleton
{
private static $_instances;
public static function getInstance()
{
$className = get_called_class(); // As of PHP 5.3
if(! isset(self::$_instances[$className] )) {
self::$_instances[$className] = new $className();
}
return self::$_instances[$className];
}
protected function __construct( ) {}
final private function __clone( ) {}
final private function __wakeup( ) {}
}
You can then extend from Singleton like this:
class Foo extends Singleton {
protected $_foo = 1;
public function setFoo($i) { $this->_foo = $i; }
public function getFoo() { return $this->_foo; }
}
and
class Bar extends Singleton {
protected $_foo = 1;
public function setFoo($i) { $this->_foo = $i; }
public function getFoo() { return $this->_foo; }
}
and manipulating:
$foo1 = Foo::getInstance();
$foo1->setFoo(5);
$foo2 = Foo::getInstance();
var_dump($foo2);
$bar1 = Bar::getInstance();
var_dump($bar1);
echo new ReflectionObject($foo2);
echo new ReflectionObject($bar1);
However, keep in mind that Singletons are very hard to unit-test and should be avoided if possible. See my answer here for some background:
How to remove multiple instances and just have one instance while multiple function calls in php?
Is there a use-case for singletons with database access in PHP?
It could work if your Singleton::getInstance() is supposed to return an instance of a different class.
abstract class Singleton {
public static function getInstance() {
static $instance = null;
if ( is_null($instance) ) {
$instance = new StdClass; // a different class than 'abstract class Singleton'
$instance->x = time();
}
return $instance;
}
}
$obj = Singleton::getInstance();
But I'd find that confusing. A bit like misusing abstract to combine the complexity of an abstract factory with the restraints of a singleton.
I am looking for the best way to go about testing the following static method (specifically using a Doctrine Model):
class Model_User extends Doctrine_Record
{
public static function create($userData)
{
$newUser = new self();
$newUser->fromArray($userData);
$newUser->save();
}
}
Ideally, I would use a mock object to ensure that fromArray (with the supplied user data) and save were called, but that's not possible as the method is static.
Any suggestions?
Sebastian Bergmann, the author of PHPUnit, recently had a blog post about Stubbing and Mocking Static Methods. With PHPUnit 3.5 and PHP 5.3 as well as consistent use of late static binding, you can do
$class::staticExpects($this->any())
->method('helper')
->will($this->returnValue('bar'));
Update: staticExpects is deprecated as of PHPUnit 3.8 and will be removed completely with later versions.
There is now the AspectMock library to help with this:
https://github.com/Codeception/AspectMock
$this->assertEquals('users', UserModel::tableName());
$userModel = test::double('UserModel', ['tableName' => 'my_users']);
$this->assertEquals('my_users', UserModel::tableName());
$userModel->verifyInvoked('tableName');
I would make a new class in the unit test namespace that extends the Model_User and test that. Here's an example:
Original class:
class Model_User extends Doctrine_Record
{
public static function create($userData)
{
$newUser = new self();
$newUser->fromArray($userData);
$newUser->save();
}
}
Mock Class to call in unit test(s):
use \Model_User
class Mock_Model_User extends Model_User
{
/** \PHPUnit\Framework\TestCase */
public static $test;
// This class inherits all the original classes functions.
// However, you can override the methods and use the $test property
// to perform some assertions.
}
In your unit test:
use Module_User;
use PHPUnit\Framework\TestCase;
class Model_UserTest extends TestCase
{
function testCanInitialize()
{
$userDataFixture = []; // Made an assumption user data would be an array.
$sut = new Mock_Model_User::create($userDataFixture); // calls the parent ::create method, so the real thing.
$sut::test = $this; // This is just here to show possibilities.
$this->assertInstanceOf(Model_User::class, $sut);
}
}
Found the working solution, would to share it despite the topic is old.
class_alias can substitute classes which are not autoloaded yet (works only if you use autoloading, not include/require files directly).
For example, our code:
class MyClass
{
public function someAction() {
StaticHelper::staticAction();
}
}
Our test:
class MyClassTest
{
public function __construct() {
// works only if StaticHelper is not autoloaded yet!
class_alias(StaticHelperMock::class, StaticHelper::class);
}
public function test_some_action() {
$sut = new MyClass();
$myClass->someAction();
}
}
Our mock:
class StaticHelperMock
{
public static function staticAction() {
// here implement the mock logic, e.g return some pre-defined value, etc
}
}
This simple solution doesn't need any special libs or extensions.
Mockery's Alias functionality can be used to mock public static methods
http://docs.mockery.io/en/latest/reference/creating_test_doubles.html#creating-test-doubles-aliasing
Another possible approach is with the Moka library:
$modelClass = Moka::mockClass('Model_User', [
'fromArray' => null,
'save' => null
]);
$modelClass::create('DATA');
$this->assertEquals(['DATA'], $modelClass::$moka->report('fromArray')[0]);
$this->assertEquals(1, sizeof($modelClass::$moka->report('save')));
One more approach:
class Experiment
{
public static function getVariant($userId, $experimentName)
{
$experiment = self::loadExperimentJson($experimentName):
return $userId % 10 > 5; // some sort of bucketing
}
protected static function loadExperimentJson($experimentName)
{
// ... do something
}
}
In my ExperimentTest.php
class ExperimentTest extends \Experiment
{
public static function loadExperimentJson($experimentName)
{
return "{
"name": "TestExperiment",
"variants": ["a", "b"],
... etc
}"
}
}
And then I would use it like so:
public function test_Experiment_getVariantForExperiment()
{
$variant = ExperimentTest::getVariant(123, 'blah');
$this->assertEquals($variant, 'a');
$variant = ExperimentTest::getVariant(124, 'blah');
$this->assertEquals($variant, 'b');
}
Testing static methods is generally considered as a bit hard (as you probably already noticed), especially before PHP 5.3.
Could you not modify your code to not use static a method ? I don't really see why you're using a static method here, in fact ; this could probably be re-written to some non-static code, could it not ?
For instance, could something like this not do the trick :
class Model_User extends Doctrine_Record
{
public function saveFromArray($userData)
{
$this->fromArray($userData);
$this->save();
}
}
Not sure what you'll be testing ; but, at least, no static method anymore...