| commit | author | age | ||
| 2207d6 | 1 | # Prophecy |
| W | 2 | |
| 3 | [](https://packagist.org/packages/phpspec/prophecy) | |
| 4 | [](https://travis-ci.org/phpspec/prophecy) | |
| 5 | ||
| 6 | Prophecy is a highly opinionated yet very powerful and flexible PHP object mocking | |
| 7 | framework. Though initially it was created to fulfil phpspec2 needs, it is flexible | |
| 8 | enough to be used inside any testing framework out there with minimal effort. | |
| 9 | ||
| 10 | ## A simple example | |
| 11 | ||
| 12 | ```php | |
| 13 | <?php | |
| 14 | ||
| 15 | class UserTest extends PHPUnit_Framework_TestCase | |
| 16 | { | |
| 17 | private $prophet; | |
| 18 | ||
| 19 | public function testPasswordHashing() | |
| 20 | { | |
| 21 | $hasher = $this->prophet->prophesize('App\Security\Hasher'); | |
| 22 | $user = new App\Entity\User($hasher->reveal()); | |
| 23 | ||
| 24 | $hasher->generateHash($user, 'qwerty')->willReturn('hashed_pass'); | |
| 25 | ||
| 26 | $user->setPassword('qwerty'); | |
| 27 | ||
| 28 | $this->assertEquals('hashed_pass', $user->getPassword()); | |
| 29 | } | |
| 30 | ||
| 31 | protected function setup() | |
| 32 | { | |
| 33 | $this->prophet = new \Prophecy\Prophet; | |
| 34 | } | |
| 35 | ||
| 36 | protected function tearDown() | |
| 37 | { | |
| 38 | $this->prophet->checkPredictions(); | |
| 39 | } | |
| 40 | } | |
| 41 | ``` | |
| 42 | ||
| 43 | ## Installation | |
| 44 | ||
| 45 | ### Prerequisites | |
| 46 | ||
| 47 | Prophecy requires PHP 5.3.3 or greater. | |
| 48 | ||
| 49 | ### Setup through composer | |
| 50 | ||
| 51 | First, add Prophecy to the list of dependencies inside your `composer.json`: | |
| 52 | ||
| 53 | ```json | |
| 54 | { | |
| 55 | "require-dev": { | |
| 56 | "phpspec/prophecy": "~1.0" | |
| 57 | } | |
| 58 | } | |
| 59 | ``` | |
| 60 | ||
| 61 | Then simply install it with composer: | |
| 62 | ||
| 63 | ```bash | |
| 64 | $> composer install --prefer-dist | |
| 65 | ``` | |
| 66 | ||
| 67 | You can read more about Composer on its [official webpage](http://getcomposer.org). | |
| 68 | ||
| 69 | ## How to use it | |
| 70 | ||
| 71 | First of all, in Prophecy every word has a logical meaning, even the name of the library | |
| 72 | itself (Prophecy). When you start feeling that, you'll become very fluid with this | |
| 73 | tool. | |
| 74 | ||
| 75 | For example, Prophecy has been named that way because it concentrates on describing the future | |
| 76 | behavior of objects with very limited knowledge about them. But as with any other prophecy, | |
| 77 | those object prophecies can't create themselves - there should be a Prophet: | |
| 78 | ||
| 79 | ```php | |
| 80 | $prophet = new Prophecy\Prophet; | |
| 81 | ``` | |
| 82 | ||
| 83 | The Prophet creates prophecies by *prophesizing* them: | |
| 84 | ||
| 85 | ```php | |
| 86 | $prophecy = $prophet->prophesize(); | |
| 87 | ``` | |
| 88 | ||
| 89 | The result of the `prophesize()` method call is a new object of class `ObjectProphecy`. Yes, | |
| 90 | that's your specific object prophecy, which describes how your object would behave | |
| 91 | in the near future. But first, you need to specify which object you're talking about, | |
| 92 | right? | |
| 93 | ||
| 94 | ```php | |
| 95 | $prophecy->willExtend('stdClass'); | |
| 96 | $prophecy->willImplement('SessionHandlerInterface'); | |
| 97 | ``` | |
| 98 | ||
| 99 | There are 2 interesting calls - `willExtend` and `willImplement`. The first one tells | |
| 100 | object prophecy that our object should extend specific class, the second one says that | |
| 101 | it should implement some interface. Obviously, objects in PHP can implement multiple | |
| 102 | interfaces, but extend only one parent class. | |
| 103 | ||
| 104 | ### Dummies | |
| 105 | ||
| 106 | Ok, now we have our object prophecy. What can we do with it? First of all, we can get | |
| 107 | our object *dummy* by revealing its prophecy: | |
| 108 | ||
| 109 | ```php | |
| 110 | $dummy = $prophecy->reveal(); | |
| 111 | ``` | |
| 112 | ||
| 113 | The `$dummy` variable now holds a special dummy object. Dummy objects are objects that extend | |
| 114 | and/or implement preset classes/interfaces by overriding all their public methods. The key | |
| 115 | point about dummies is that they do not hold any logic - they just do nothing. Any method | |
| 116 | of the dummy will always return `null` and the dummy will never throw any exceptions. | |
| 117 | Dummy is your friend if you don't care about the actual behavior of this double and just need | |
| 118 | a token object to satisfy a method typehint. | |
| 119 | ||
| 120 | You need to understand one thing - a dummy is not a prophecy. Your object prophecy is still | |
| 121 | assigned to `$prophecy` variable and in order to manipulate with your expectations, you | |
| 122 | should work with it. `$dummy` is a dummy - a simple php object that tries to fulfil your | |
| 123 | prophecy. | |
| 124 | ||
| 125 | ### Stubs | |
| 126 | ||
| 127 | Ok, now we know how to create basic prophecies and reveal dummies from them. That's | |
| 128 | awesome if we don't care about our _doubles_ (objects that reflect originals) | |
| 129 | interactions. If we do, we need to use *stubs* or *mocks*. | |
| 130 | ||
| 131 | A stub is an object double, which doesn't have any expectations about the object behavior, | |
| 132 | but when put in specific environment, behaves in specific way. Ok, I know, it's cryptic, | |
| 133 | but bear with me for a minute. Simply put, a stub is a dummy, which depending on the called | |
| 134 | method signature does different things (has logic). To create stubs in Prophecy: | |
| 135 | ||
| 136 | ```php | |
| 137 | $prophecy->read('123')->willReturn('value'); | |
| 138 | ``` | |
| 139 | ||
| 140 | Oh wow. We've just made an arbitrary call on the object prophecy? Yes, we did. And this | |
| 141 | call returned us a new object instance of class `MethodProphecy`. Yep, that's a specific | |
| 142 | method with arguments prophecy. Method prophecies give you the ability to create method | |
| 143 | promises or predictions. We'll talk about method predictions later in the _Mocks_ section. | |
| 144 | ||
| 145 | #### Promises | |
| 146 | ||
| 147 | Promises are logical blocks, that represent your fictional methods in prophecy terms | |
| 148 | and they are handled by the `MethodProphecy::will(PromiseInterface $promise)` method. | |
| 149 | As a matter of fact, the call that we made earlier (`willReturn('value')`) is a simple | |
| 150 | shortcut to: | |
| 151 | ||
| 152 | ```php | |
| 153 | $prophecy->read('123')->will(new Prophecy\Promise\ReturnPromise(array('value'))); | |
| 154 | ``` | |
| 155 | ||
| 156 | This promise will cause any call to our double's `read()` method with exactly one | |
| 157 | argument - `'123'` to always return `'value'`. But that's only for this | |
| 158 | promise, there's plenty others you can use: | |
| 159 | ||
| 160 | - `ReturnPromise` or `->willReturn(1)` - returns a value from a method call | |
| 161 | - `ReturnArgumentPromise` or `->willReturnArgument($index)` - returns the nth method argument from call | |
| 162 | - `ThrowPromise` or `->willThrow($exception)` - causes the method to throw specific exception | |
| 163 | - `CallbackPromise` or `->will($callback)` - gives you a quick way to define your own custom logic | |
| 164 | ||
| 165 | Keep in mind, that you can always add even more promises by implementing | |
| 166 | `Prophecy\Promise\PromiseInterface`. | |
| 167 | ||
| 168 | #### Method prophecies idempotency | |
| 169 | ||
| 170 | Prophecy enforces same method prophecies and, as a consequence, same promises and | |
| 171 | predictions for the same method calls with the same arguments. This means: | |
| 172 | ||
| 173 | ```php | |
| 174 | $methodProphecy1 = $prophecy->read('123'); | |
| 175 | $methodProphecy2 = $prophecy->read('123'); | |
| 176 | $methodProphecy3 = $prophecy->read('321'); | |
| 177 | ||
| 178 | $methodProphecy1 === $methodProphecy2; | |
| 179 | $methodProphecy1 !== $methodProphecy3; | |
| 180 | ``` | |
| 181 | ||
| 182 | That's interesting, right? Now you might ask me how would you define more complex | |
| 183 | behaviors where some method call changes behavior of others. In PHPUnit or Mockery | |
| 184 | you do that by predicting how many times your method will be called. In Prophecy, | |
| 185 | you'll use promises for that: | |
| 186 | ||
| 187 | ```php | |
| 188 | $user->getName()->willReturn(null); | |
| 189 | ||
| 190 | // For PHP 5.4 | |
| 191 | $user->setName('everzet')->will(function () { | |
| 192 | $this->getName()->willReturn('everzet'); | |
| 193 | }); | |
| 194 | ||
| 195 | // For PHP 5.3 | |
| 196 | $user->setName('everzet')->will(function ($args, $user) { | |
| 197 | $user->getName()->willReturn('everzet'); | |
| 198 | }); | |
| 199 | ||
| 200 | // Or | |
| 201 | $user->setName('everzet')->will(function ($args) use ($user) { | |
| 202 | $user->getName()->willReturn('everzet'); | |
| 203 | }); | |
| 204 | ``` | |
| 205 | ||
| 206 | And now it doesn't matter how many times or in which order your methods are called. | |
| 207 | What matters is their behaviors and how well you faked it. | |
| 208 | ||
| 209 | #### Arguments wildcarding | |
| 210 | ||
| 211 | The previous example is awesome (at least I hope it is for you), but that's not | |
| 212 | optimal enough. We hardcoded `'everzet'` in our expectation. Isn't there a better | |
| 213 | way? In fact there is, but it involves understanding what this `'everzet'` | |
| 214 | actually is. | |
| 215 | ||
| 216 | You see, even if method arguments used during method prophecy creation look | |
| 217 | like simple method arguments, in reality they are not. They are argument token | |
| 218 | wildcards. As a matter of fact, `->setName('everzet')` looks like a simple call just | |
| 219 | because Prophecy automatically transforms it under the hood into: | |
| 220 | ||
| 221 | ```php | |
| 222 | $user->setName(new Prophecy\Argument\Token\ExactValueToken('everzet')); | |
| 223 | ``` | |
| 224 | ||
| 225 | Those argument tokens are simple PHP classes, that implement | |
| 226 | `Prophecy\Argument\Token\TokenInterface` and tell Prophecy how to compare real arguments | |
| 227 | with your expectations. And yes, those classnames are damn big. That's why there's a | |
| 228 | shortcut class `Prophecy\Argument`, which you can use to create tokens like that: | |
| 229 | ||
| 230 | ```php | |
| 231 | use Prophecy\Argument; | |
| 232 | ||
| 233 | $user->setName(Argument::exact('everzet')); | |
| 234 | ``` | |
| 235 | ||
| 236 | `ExactValueToken` is not very useful in our case as it forced us to hardcode the username. | |
| 237 | That's why Prophecy comes bundled with a bunch of other tokens: | |
| 238 | ||
| 239 | - `IdenticalValueToken` or `Argument::is($value)` - checks that the argument is identical to a specific value | |
| 240 | - `ExactValueToken` or `Argument::exact($value)` - checks that the argument matches a specific value | |
| 241 | - `TypeToken` or `Argument::type($typeOrClass)` - checks that the argument matches a specific type or | |
| 242 | classname | |
| 243 | - `ObjectStateToken` or `Argument::which($method, $value)` - checks that the argument method returns | |
| 244 | a specific value | |
| 245 | - `CallbackToken` or `Argument::that(callback)` - checks that the argument matches a custom callback | |
| 246 | - `AnyValueToken` or `Argument::any()` - matches any argument | |
| 247 | - `AnyValuesToken` or `Argument::cetera()` - matches any arguments to the rest of the signature | |
| 248 | - `StringContainsToken` or `Argument::containingString($value)` - checks that the argument contains a specific string value | |
| 249 | ||
| 250 | And you can add even more by implementing `TokenInterface` with your own custom classes. | |
| 251 | ||
| 252 | So, let's refactor our initial `{set,get}Name()` logic with argument tokens: | |
| 253 | ||
| 254 | ```php | |
| 255 | use Prophecy\Argument; | |
| 256 | ||
| 257 | $user->getName()->willReturn(null); | |
| 258 | ||
| 259 | // For PHP 5.4 | |
| 260 | $user->setName(Argument::type('string'))->will(function ($args) { | |
| 261 | $this->getName()->willReturn($args[0]); | |
| 262 | }); | |
| 263 | ||
| 264 | // For PHP 5.3 | |
| 265 | $user->setName(Argument::type('string'))->will(function ($args, $user) { | |
| 266 | $user->getName()->willReturn($args[0]); | |
| 267 | }); | |
| 268 | ||
| 269 | // Or | |
| 270 | $user->setName(Argument::type('string'))->will(function ($args) use ($user) { | |
| 271 | $user->getName()->willReturn($args[0]); | |
| 272 | }); | |
| 273 | ``` | |
| 274 | ||
| 275 | That's it. Now our `{set,get}Name()` prophecy will work with any string argument provided to it. | |
| 276 | We've just described how our stub object should behave, even though the original object could have | |
| 277 | no behavior whatsoever. | |
| 278 | ||
| 279 | One last bit about arguments now. You might ask, what happens in case of: | |
| 280 | ||
| 281 | ```php | |
| 282 | use Prophecy\Argument; | |
| 283 | ||
| 284 | $user->getName()->willReturn(null); | |
| 285 | ||
| 286 | // For PHP 5.4 | |
| 287 | $user->setName(Argument::type('string'))->will(function ($args) { | |
| 288 | $this->getName()->willReturn($args[0]); | |
| 289 | }); | |
| 290 | ||
| 291 | // For PHP 5.3 | |
| 292 | $user->setName(Argument::type('string'))->will(function ($args, $user) { | |
| 293 | $user->getName()->willReturn($args[0]); | |
| 294 | }); | |
| 295 | ||
| 296 | // Or | |
| 297 | $user->setName(Argument::type('string'))->will(function ($args) use ($user) { | |
| 298 | $user->getName()->willReturn($args[0]); | |
| 299 | }); | |
| 300 | ||
| 301 | $user->setName(Argument::any())->will(function () { | |
| 302 | }); | |
| 303 | ``` | |
| 304 | ||
| 305 | Nothing. Your stub will continue behaving the way it did before. That's because of how | |
| 306 | arguments wildcarding works. Every argument token type has a different score level, which | |
| 307 | wildcard then uses to calculate the final arguments match score and use the method prophecy | |
| 308 | promise that has the highest score. In this case, `Argument::type()` in case of success | |
| 309 | scores `5` and `Argument::any()` scores `3`. So the type token wins, as does the first | |
| 310 | `setName()` method prophecy and its promise. The simple rule of thumb - more precise token | |
| 311 | always wins. | |
| 312 | ||
| 313 | #### Getting stub objects | |
| 314 | ||
| 315 | Ok, now we know how to define our prophecy method promises, let's get our stub from | |
| 316 | it: | |
| 317 | ||
| 318 | ```php | |
| 319 | $stub = $prophecy->reveal(); | |
| 320 | ``` | |
| 321 | ||
| 322 | As you might see, the only difference between how we get dummies and stubs is that with | |
| 323 | stubs we describe every object conversation instead of just agreeing with `null` returns | |
| 324 | (object being *dummy*). As a matter of fact, after you define your first promise | |
| 325 | (method call), Prophecy will force you to define all the communications - it throws | |
| 326 | the `UnexpectedCallException` for any call you didn't describe with object prophecy before | |
| 327 | calling it on a stub. | |
| 328 | ||
| 329 | ### Mocks | |
| 330 | ||
| 331 | Now we know how to define doubles without behavior (dummies) and doubles with behavior, but | |
| 332 | no expectations (stubs). What's left is doubles for which we have some expectations. These | |
| 333 | are called mocks and in Prophecy they look almost exactly the same as stubs, except that | |
| 334 | they define *predictions* instead of *promises* on method prophecies: | |
| 335 | ||
| 336 | ```php | |
| 337 | $entityManager->flush()->shouldBeCalled(); | |
| 338 | ``` | |
| 339 | ||
| 340 | #### Predictions | |
| 341 | ||
| 342 | The `shouldBeCalled()` method here assigns `CallPrediction` to our method prophecy. | |
| 343 | Predictions are a delayed behavior check for your prophecies. You see, during the entire lifetime | |
| 344 | of your doubles, Prophecy records every single call you're making against it inside your | |
| 345 | code. After that, Prophecy can use this collected information to check if it matches defined | |
| 346 | predictions. You can assign predictions to method prophecies using the | |
| 347 | `MethodProphecy::should(PredictionInterface $prediction)` method. As a matter of fact, | |
| 348 | the `shouldBeCalled()` method we used earlier is just a shortcut to: | |
| 349 | ||
| 350 | ```php | |
| 351 | $entityManager->flush()->should(new Prophecy\Prediction\CallPrediction()); | |
| 352 | ``` | |
| 353 | ||
| 354 | It checks if your method of interest (that matches both the method name and the arguments wildcard) | |
| 355 | was called 1 or more times. If the prediction failed then it throws an exception. When does this | |
| 356 | check happen? Whenever you call `checkPredictions()` on the main Prophet object: | |
| 357 | ||
| 358 | ```php | |
| 359 | $prophet->checkPredictions(); | |
| 360 | ``` | |
| 361 | ||
| 362 | In PHPUnit, you would want to put this call into the `tearDown()` method. If no predictions | |
| 363 | are defined, it would do nothing. So it won't harm to call it after every test. | |
| 364 | ||
| 365 | There are plenty more predictions you can play with: | |
| 366 | ||
| 367 | - `CallPrediction` or `shouldBeCalled()` - checks that the method has been called 1 or more times | |
| 368 | - `NoCallsPrediction` or `shouldNotBeCalled()` - checks that the method has not been called | |
| 369 | - `CallTimesPrediction` or `shouldBeCalledTimes($count)` - checks that the method has been called | |
| 370 | `$count` times | |
| 371 | - `CallbackPrediction` or `should($callback)` - checks the method against your own custom callback | |
| 372 | ||
| 373 | Of course, you can always create your own custom prediction any time by implementing | |
| 374 | `PredictionInterface`. | |
| 375 | ||
| 376 | ### Spies | |
| 377 | ||
| 378 | The last bit of awesomeness in Prophecy is out-of-the-box spies support. As I said in the previous | |
| 379 | section, Prophecy records every call made during the double's entire lifetime. This means | |
| 380 | you don't need to record predictions in order to check them. You can also do it | |
| 381 | manually by using the `MethodProphecy::shouldHave(PredictionInterface $prediction)` method: | |
| 382 | ||
| 383 | ```php | |
| 384 | $em = $prophet->prophesize('Doctrine\ORM\EntityManager'); | |
| 385 | ||
| 386 | $controller->createUser($em->reveal()); | |
| 387 | ||
| 388 | $em->flush()->shouldHaveBeenCalled(); | |
| 389 | ``` | |
| 390 | ||
| 391 | Such manipulation with doubles is called spying. And with Prophecy it just works. | |
