撰寫單元測試
預期測試時會遇到 error
$this->expectWarning();
// Warning: Division by zero
$a = 2 / 0;
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撰寫單元測試
Fixtures
建立待測對象 (data structure / object) 並初始化
測試對象需要在每個 test case 執行前 reset
測試開始前給定測試用資料
降低不同 test case 互相影響 ( 依賴 ) 產生的問題
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撰寫單元測試
public function setUp() {
$this->stack = new SplStack();
$this->stack->push(1);
$this->stack->push(2);
}
public function tearDown() {
$this->stack = null;
}
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撰寫單元測試
public function setUp() {
$this->stack = new SplStack();
$this->stack->push(1);
$this->stack->push(2);
}
public function testStack() {
$this->stack->count(); // int(2)
}
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撰寫單元測試
public function test1() {
$this->stack->push('str');
$this->stack->count(); // int(3)
}
public fcuntion test2() {
$this->stack->count(); // int(2)
}
---- $this->stack 會在 test case 執行完成以後被 reset -----
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撰寫單元測試
會用到 fixture 的情形
受測對象中不同的狀態 (state)
例如： NEW, DRAFT, PUBLISHED
Test case 執行後會導致受測對象狀態異動
受測對象需要初始化
或是要事先給定資料
Test Doubles
功能越簡單越好
不要為了 test doubles 再寫 unit test
class FakeMemcacahe {
function get($key) {};
function set($key, $val) {};
function keys() {};
.....
}
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單元測試 (Unit Test)
並非所有的 code 都有辦法建立 test case
Unit test 通過只能表示各項小功能正確
無法代表整個專案可以正確執行
靠整合測試來檢查整體行為是否如預期
SOLID Principles in OOP
Single responsibility
Open-closed
Liskov Substitution
Interface Segregation
Dependency Inversion
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Single responsibility
單一職責原則
物件指處理單一類型的工作
高內聚
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Single responsibility
Class User {
function getUserById();
function getUserByName();
function createUser();
}
僅處理 user
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Single responsibility
Class User {
function getUserById();
function getUserByName();
function createUser();
function getUserByOrderId();
}
歪了
可能要建立 stub
Open-closed
class User {
protected $users = [];
}
class UserList extends User
implements Traversable {
protected $currentIndex = 0;
function current();
function next();
....
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Open-closed
class TaskQueue {
public $tasks;
function pop();
function push();
}
$queue->$task[] = new Task();
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Open-closed
class TaskQueue {
public $tasks;
function pop();
function push();
}
$queue->$task[] = new Task();
違反封閉原則
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Open-closed
class TaskQueue {
private $tasks;
function pop();
function push();
}
$queue->push(new Task());
透過 interface 操作
Liskov Substitution
class Animal {}
class Food {}
class DogFood extends Food {}
class CatFood extends Food {}
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Liskov Substitution
class Dog extends Animal {
public function eat($food) {
if (!$food instanceof DogFood) {
throw new
DogFoodException();
}
class Cat extends Animal {
public function eat(Food $food) {
... throw new CatFoodException();
Liskov Substitution
class Animal {
public function eat (Food $food) {}
}
class Dog extends Animal {
public function eat($food) {
if (!$food instanceof DogFood) {
parent::eat();
}
}
Interface Segregation
interface DogInterface() {
function walk();
function sleep();
}
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Interface Segregation
class Dog implements DogInterface {
public function walk() {
return 'walking ...';
}
public function sleep() {
return '.. zz ZZ';
}
}
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Interface Segregation
class RobotDog implements DogInterface {
public function walk() {
return 'walking ...';
}
public function sleep() {
throw new Exception();
}
}
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Interface Segregation
interface walkable () {
function walk();
}
interface sleepable () {
function sleep();
}
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Interface Segregation
class Dog implements walkable,
sleepable {
}
class RobotDog implements walkable {
}
Dependency Inversion
class User {
function getByFile(File $reader) {}
function getByAws(AwsS3 $reader) {}
function getByDb(MySQL $reader) {}
}
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Dependency Inversion
class User {
function getByFile(File $reader) {}
function getByAws(AwsS3 $reader) {}
function getByDb(MySQL $reader) {}
}
User 類別需要知道各種 reader 的實作方
式
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Dependency Inversion
User File
AWS S3
MySQL
User 與 3 個類別相依
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Dependency Inversion
Interface ReaderInterface {
function open();
function read();
function save();
}
class File implements ReaderInterface;
class AwsS3 implements ReaderInterface;
class MySQL implements ReaderInterface;
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Dependency Inversion
class User {
function get(ReaderInterface $reader){
$reader->open();
$users = $reader->read();
}
}
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Dependency Inversion
User File
AWS S3
MySQL
ReaderInterface
每個類別只和 1 個 interface 有相依關係