I have the following super simple Redux-Saga that I want to test with Jest.
function* nextApi() {
yield* takeEvery(
(action) => !!(action.meta && action.meta.next),
nextApiSaga
)
}
I've looked at Redux-Sagas-Test-Plan, but that only seems to allow you to unit test functions that contain Saga Effect Creators and doesn't seem to support Saga Helpers. There is also Redux-Saga-Test but that just does a deepEqual on the yielded effect and doesn't test the arrow function.
What I want to be able to do is past the following two objects to takeEvery and see that nextApiSaga is only called in the second case.
{ type: 'foo' }
{ type: 'foo', meta: { next: 'bar' } }
I left you a comment about redux-saga-test-plan having methods for saga helpers, but you can easily test takeEvery with it. Call testSaga with your saga and then invoke the takeEvery method assertion with the pattern (note I keep a reference to your original anonymous function) and the other saga.
const helper = action => !!(action.meta && action.meta.next)
function* nextApi() {
yield* takeEvery(
helper,
nextApiSaga
)
}
testSaga(nextApi).takeEvery(helper, nextApiSaga)
Taking a different approach, I came up with this. Not sure if it's the best answer, but it seems to work. Adding here in case anyone else has the same problem and still open to better suggestions.
function getTakeEveryFunction(saga) {
return saga().next().value.TAKE.pattern
}
it('takes actions with meta.next property', () => {
const func = getTakeEveryFunction(nextApi)
expect(func({ type:'foo' })).toBe(false)
expect(func({ type:'foo', meta: { next: 'bar' } })).toBe(true)
})
Related
I have an interface that communicates with my presenter who checks whether the fields of a form are valid.
My interface is:
interface MainView {
fun showMessage(data: LoginEntity)
fun showEmailError()
fun showPasswordError()
}
My method in the presenter is like that:
fun sendForm(loginData: LoginDataPresentation, view: MainView) {
if (isValid()) {
view.showMessage(mapData(loginData))
} else if (isValidPassword()) {
view.showPasswordError()
} else {
view.showEmailError()
}
}
My test class with KotlinTest:
class LoginPresentationKtTest : StringSpec() {
init {
"given a bunch of Login Data should be matched successfully" {
forAll(EmailGenerator(), PasswordGenerator(), { email: String, password: String ->
val loginData: LoginDataPresentation(email, password)
val mockMainView = mockMainView()
sendForm(loginData, mockMainView())
})
}
}
private fun mockMainView(): MainView {
//How to mock?????
}
}
Using the KotlinTest library, is there any way to verify that the call to the showMessage method of the MainView class is done provided that the email and password generated is always correct? Is it possible to use a mock library like mockito?
With the response of the user #mkobit, the following modification can be made using Mockito-Kotlin, with which the test would be as follows:
class LoginPresentationKtTest : StringSpec() {
init {
"given a bunch of Login Data should be matched successfully" {
forAll(EmailGenerator(), PasswordGenerator(), { email: String, password: String ->
val loginData = LoginDataPresentation(email, password)
val mockMainView = Mockito.mock(MainView::class.java)
sendForm(loginData, mockMainView)
verify(mockMainView).showMessage()
true
})
}
}
}
At each execution of the loop, it will be checked if the verify () function has been called. If the execution flow is the expected one, it will proceed to the next execution of the loop. If the verify () function fails, an error will occur in the console indicating that the test has failed.
Is there any better solution?
You mentioned Mockito, so I'll show you can example. I'm going to also use the nhaarman/mockito-kotlin library that makes it more expressive and easier to use in Kotlin.
import com.nhaarman.mockito_kotlin.mock
val mockMainView: MainView = mock()
This is basically equivalent to val mockMainView = Mockito.mock(MainView::class.java) from Mockito.
In Kotlin, we can get a more concise and compact code due to some of its features.
If you want to do some stubbing (like return values, exceptions, etc.) you could use the whenever (Mockito.when(T methodCall)) API.
See the documentation for details.
I'm going to skip that for now.
So, now you would call for method:
sendForm(loginData, mockMainView)
Then, you can perform verification.
Using mockito-kotlin method verify (Mockito.verify(T mock)) the behavior.
import com.nhaarman.mockito_kotlin.verify
verify(mockMainView).showPasswordError()
verify(mockMainView).showEmailError()
Using any() (Mockito.any(Class<T> type)) to not just verify method is called with any value.
import com.nhaarman.mockito_kotlin.any
verify(mockMainView).showMessage(any())
There is support for other argument matchers if you want to be more explicit with what is being passed in.
Note that Mockito also supports opt-in mocking of final classes/methods.
The example for Gradle would be something like adding a file to src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker with the contents of mock-maker-inline.
References:
Mockito Javadoc
mockito-kotlin Wiki documentation
When I tried to do unit testing for private methods in a Class getting error as private methods are only accessible inside the class. Here I added sample snippet for my class and mocha test. Kindly provide me solution to implement unit test for private methods.
Class Name: Notification.ts
class Notification {
constructor() {}
public validateTempalte() {
return true;
}
private replacePlaceholder() {
return true;
}
}
Unit Test:
import {Notification} from 'Notification';
import * as chai from "chai";
describe("Notification", function(){
describe('#validateTempalte - Validate template', function() {
it('it should return success', function() {
const result = new Notification()
chai.expect(result.validateTempalte()).to.be.equal(true);
});
});
describe('#replacePlaceholder - Replace Placeholder', function() {
it('it should return success', function() {
const result = new Notification()
// As expected getting error "Private is only accessible within class"
chai.expect(result.replacePlaceholder()).to.be.equal(true);
});
});
});
As a workaround, currently, I am changing access specifier of function replacePlaceholder to public. But I don't think its a valid approach.
A possible solution to omit Typescript checks is to access the property dynamically (Not telling wether its good).
myClass['privateProp'] or for methods: myClass['privateMethod']()
Technically, in current versions of TypeScript private methods are only compile-time checked to be private - so you can call them.
class Example {
public publicMethod() {
return 'public';
}
private privateMethod() {
return 'private';
}
}
const example = new Example();
console.log(example.publicMethod()); // 'public'
console.log(example.privateMethod()); // 'private'
I mention this only because you asked how to do it, and that is how you could do it.
Correct Answer
However, that private method must be called by some other method... otherwise it isn't called at all. If you test the behaviour of that other method, you will cover the private method in the context it is used.
If you specifically test private methods, your tests will become tightly coupled to the implementation details (i.e. a good test wouldn't need to be changed if you refactored the implementation).
Disclaimer
If you still test it at the private method level, the compiler might in the future change and make the test fail (i.e. if the compiler made the method "properly" private, or if a future version of ECMAScript added visibility keywords, etc).
In my case, I use the prototype of the object to get access to a private method. It works well and TS does not swear.
For example:
class Example {
private privateMethod() {}
}
describe() {
it('test', () => {
const example = new Example();
const exampleProto = Object.getPrototypeOf(example);
exampleProto.privateMethod();
})
}
If you use a static method then use exampleProto.constructor.privateMethod();.
In HolgerJeromin's comment, the comment issue has a succinct solution that still uses the property syntax.
The solution is to type cast your object / class to any.
Examples:
(<any>myClass).privateMethod();
const value = (<any>myClass).privateValue;
(myClass as any).privateMethod();
const value = (myClass as any).privateValue;
This method satisfies the compiler as well as the VSCode syntax highlighting.
Here are some of my notes from the issue that talks about this
Accessing via a string is more common, although I don't see why it might be more typesafe.
These features are done deliberately, therefore they are helping more than hindering.
There is probably a way to disable this type of feature so people don't copy and paste this code into production. "noImplicitAny": true, might help in the tsconfig.json
Extract out the private function into a separate/stand alone function, but don't export it externally.
This is somewhat semantically correct, since after all — a private function is private and should not be accessed by anyone except the class itself.
My subjective solution: you could define a new testing-only interface that extends the original one by adding the private methods as (implicitly public) interface methods. Then, you cast the instantiated object to this new test type. This satisfies both tsc and VS code type checking. Your example with my solution:
interface INotification {
validateTemplate(): boolean,
}
class Notification implements INotification {
constructor() {}
public validateTemplate() {
return true;
}
private replacePlaceholder() {
return true;
}
}
Testing:
import {Notification} from 'Notification';
import * as chai from "chai";
interface INotificationTest extends INotification {
replacePlaceholder(): boolean;
}
describe("Notification", function(){
describe('#validateTemplate - Validate template', function() {
it('it should return success', function() {
const result = new Notification() as INotificationTest;
chai.expect(result.validateTemplate()).to.be.equal(true);
});
});
describe('#replacePlaceholder - Replace Placeholder', function() {
it('it should return success', function() {
const result = new Notification() as INotificationTest;
// Works!
chai.expect(result.replacePlaceholder()).to.be.equal(true);
});
});
});
Advantages:
tsc and vs code do not complain
IntelliSense (or any other autocomplete) works
simple (subjectively)
If you don't want to define the original interface (INotification), you could just fully define the test one (INotificationTest) instead of extending and cast it in the same manner.
Disadvantages:
Added boilerplate
Need to have both of the interfaces updated and in sync
Potentially introducing bugs by explicitly casting as a non original type.
I leave it up to you to decide whether this is worth it or no. In my case, the positives outweigh the negatives. I have tested this with jest, but I assume that mocha.js is no different here.
Edit: but generally I would agree with Fenton's answer
// module.ts
private async privateMethod = () => "private method executed"
public async testPrivateMethods(...args) {
if (process.env.NODE_ENV === 'development') {
return this.privateMethod(...args);
}
}
Now we can reach our private method to test. In jest file:
// module.spec.js
describe('Module', () => {
let service: Module = new Module();
it('private method should be defined', () => {
expect(service.testPrivateMethods).toBeDefined();
});
}
You need to set your enviroment variable name of NODE_ENV must be development.
// .env
NODE_ENV="development"
The fun thing is that it's just a typescript error (not javascript), so you can fix it with
// #ts-expect-error
and everything works fine.
I consider it as a legitimate solution, as the goal was to suppress typescript in this particular case.
Since private methods are not accessible outside class, you can have another public method which calls replacePlaceholder() in Notification class and then test the public method.
I'm using the native Bluetooth serial library and trying to mock data for testing in the browser. By experimentation (and a little reading) it seems that the way to do this is to check for the 'cordova' platform:
export class BluetoothServiceWrapper implements OnDestroy, OnChanges {
...
private isEmulated:boolean = true;
...
constructor(platform:Platform) {
platform.ready().then(() => {
this.isEmulated = !platform.is('cordova');
});
}
The strange thing is that this works in some parts:
connect(device:BluetoothDevice) {
return Observable.create(observer => {
...
if (!this.isEmulated) {
...
}else{
... // this is executed in the browser
}
}
}
But in other parts the this.isEmulated is undefined:
write(data:any):Promise<any> {
if (!this.isEmulated) {
return BluetoothSerial.write(data);
} else {
.... // this never gets executed
}
}
Am I overcomplicating this and there is an easier way to check if we are using browser/emulation? Or is there some error in the way the context is being passed over?
I should mention that both methods get the same members when accessing 'this' i.e. the BluetoothServiceWrapper members. In the case of the 'write' function though the isEmulated variable is hidden/undefined.
Ok, this was a bit of a trap. The important piece of information that was missing from the original post was that I had another component/service perform the following:
if (!this.isConnected && (!this.isConnecting)) {
this.bluetoothServiceWrapper.connect(device).subscribe(data => this.tuningModuleService.onData(data), console.error);
this.tuningModuleService.setOutputFunction(this.bluetoothServiceWrapper.write);
}
Inside the service above I would be calling this.write('somedata'), using the function above given as reference.
The service:
outputToSerialFn: any;
constructor(applicationRef: ApplicationRef, platform: Platform) {
...
// default (mock) output function
this.outputToSerialFn = function (data) {
return new Promise((resolve, reject) => {
console.log('Mock BT OUT', data);
})
};
}
setOutputFunction(outputToSerialFn: any) {
this.outputToSerialFn = outputToSerialFn;
}
The problem is that during calls the write function would get the scope of the Service using it instead of the BluetoothWrapper service.
One solution is to replace the call above with:
this.tuningModuleService.setOutputFunction(this.bluetoothServiceWrapper.write.bind(this.bluetoothServiceWrapper));
The key word is bind.
This is probably not the best pattern but might help someone who is also struggling with this. The lesson here is that passing functions as parameters overrides the original function scope.
I'm building a Laravel 5 application at the moment and have gotten myself confused about how to mock things in PhpSpec.
I'm building a schedule times validator that requires the intended schedule to be checked against all current schedules and see if there's any overlap (events are not allowed to overlap).
I need to pull in the schedules in question so I can test against them. At the moment it's a very basic whereBetween query, but it's going to get a lot more complicated as there'll be recurring schedules to check against as well.
So here's my stripped down class. I really just want to test the doesNotOverlap function.
use App\Schedule;
class ScheduleTimesValidator
{
protected $schedule;
public function __construct(Schedule $schedule)
{
$this->schedule = $schedule;
}
public function doesNotOverlap($slug, $intended)
{
$schedules = $this->getSchedulesBetween($slug, $intended);
if(empty($schedules)) return true;
return false;
}
protected function getSchedulesBetween($slug, $intended)
{
// Casting to array to make testing a little easier
return $this->schedule->whereIsRecurring(false)
->ofChurch($slug)
->whereBetween('start', [$intended['start'], $intended['end']])
->get()->toArray();
}
and here's my Spec
use PhpSpec\ObjectBehavior;
use Prophecy\Argument;
class ScheduleTimesValidatorSpec extends ObjectBehavior
{
protected $validIntended = [
'start' => '2015-12-01 12:00:00',
'end' => '2015-12-01 13:00:00'
];
protected $churchNonRecurringSchedules = [
['start' => '2014-11-20 13:00:00', 'end' => '2014-11-21 14:00:00'],
['start' => '2014-11-23 10:36:07', 'end' => '2014-11-23 11:36:07'],
];
function let($schedule)
{
$schedule->beADoubleOf('App\Schedule');
$this->beConstructedWith($schedule);
}
function it_is_initializable()
{
$this->shouldHaveType('App\Validation\ScheduleTimesValidator');
}
function it_should_return_true_if_it_does_not_overlap($schedule)
{
// $schedule->any()->willReturn([]);
// $schedule->whereIsRecurring()->shouldBeCalled();
// $schedule->whereIsRecurring(false)->ofChurch()->whereBetween()->get()->toArray()->willReturn([]);
// $schedule->willReturn([]);
// $this->getSchedulesBetween('slug', $this->validIntended)->willReturn([]);
$this->doesNotOverlap('slug', $this->validIntended)->shouldReturn(true);
}
// Tear Down
function letgo() {}
}
If I run it like that I get:
! it should return true if it does not overlap
method 'Double\App\Schedule\P8::whereIsRecurring()' not found.
I tried (as you can see) various commented out things to mock what $schedule will return, but that doesn't seem to work.
So I guess I want to mock the protected getSchedulesBetween method in the class, but doing things like $this->getSchedulesBetween($arg, $arg)->willReturn(blah) doesn't work.
Do I need to pull getSchedulesBetween() out of the class and move it into another class and then mock that? Or do I need to push $this->schedule->blah into the doestNotOverlap method so I can mock what $schedule will return?
I don't want to actually test the App\Schedule Laravel Model - I just want to mock what it's returning and will be hardcoding a variety of queries that will be run to get the different model results.
End of a long day here so brain a little zonked.
Update 2014-10-23
So I created a scope on my Schedule model
public function scopeSchedulesBetween($query, $slug, $intended)
{
return $query->whereIsRecurring(false)
->ofChurch($slug)
->whereBetween('start', [$intended['start'], $intended['end']]);
}
Then created a new App\Helpers\ScheduleQueryHelper which instantiated App\Schedule as a variable and added this method:
public function getSchedulesBetween($slug, $intended)
{
return $this->schedule->schedulesBetween($slug, $intended)->get()->toArray();
}
Then updated my spec to do
function let($scheduleQueryHelper)
{
$scheduleQueryHelper->beADoubleOf('App\Helpers\ScheduleQueryHelper');
$this->beConstructedWith($scheduleQueryHelper);
}
function it_should_return_true_if_it_does_not_overlap($scheduleQueryHelper)
{
$scheduleQueryHelper->getSchedulesBetween('slug', $this->validIntended)->willReturn([]);
$this->doesNotOverlap('slug', $this->validIntended)->shouldReturn(true);
}
And back in my ScheduleTimesValidator class did
public function doesNotOverlap($slug, $intended)
{
$schedules = $this->scheduleQueryHelper->getSchedulesBetween($slug, $intended);
if(empty($schedules)) {
return true;
}
return false;
}
And now PhpSpec is mocking that other class ok. However this seems like a very roundabout way to be doing things.
I'm just setting up some first unit tests, and I can't quite see how I'm trying to achieve (with my current test structure) can be done, which means I'm not sure whether my approach to the tests is incorrect, or it's just a limitation on xUnit.
I'm testing my MVC Controllers, and want to ensure that they all provide a ArgumentNullException if they are constructed passing null across as the arguments (they get resolved via Castle in the real world).
So, I've a private field on the Test class:
private IEnumerable<Type> ControllerTypes = typeof(MyBaseController).Assembly.GetTypes().Where(t => IsController(t));
Then, my test method:
[Fact]
public void EnsureControllersThrowIfProvidedWithNull() {
foreach (var controller in ControllerTypes) {
var ctrs = GetConstructorsForType(controller);
if (null == ctrs || !ctrs.Any()) { //if the controller has no constructors, that's fine, we just skip over it
continue;
}
var ctr = ctrs.ElementAt(0);
var ctrParamsAsNull = ctr.GetParameters().Select(p => (object)null);
Assert.Throws<ArgumentNullException>(() => {
ctr.Invoke(ctrParamsAsNull.ToArray());
});
}
}
So this is all working fine, I run the test runner, and one of my Controllers doesn't throw an ArgumentNullException when passed null, great, my test fails, but I don't know which controller it was, from the given output.
I do know how I can debug through the test to see which it is that fails, and can manually go through all my controllers to check which it is, but it would be useful to know which controller it was that failed.
Or am I just using a unit test wrong here?
(Side note, there's another test which ensures there's only 1 public constructor for each controller, so I can be sure I'm targeting the correct constructor when this fires, as long as that first test passed).
Thanks
Note:
There's a flaw in the logic for the test, which means it doesn't fully cover what I was expecting it too, as long as it throws an ArgumentNullException for at least 1 of the arguments, then it will pass the test, which isn't right. However as the arguments are interfaces I can't instantiate a new instance of them. So anyone looking to copy the code for the test, I wouldn't do so. Not looking for a solution to that issue here.
Assert.Throws is only helper method that executes delegate inside try catch block. You don't have to use it and you can replace it with your own implementation. Something like:
[Fact]
public void EnsureControllersThrowIfProvidedWithNull() {
foreach (var controller in ControllerTypes) {
var ctrs = GetConstructorsForType(controller);
if (null == ctrs || !ctrs.Any()) { //if the controller has no constructors, that's fine, we just skip over it
continue;
}
var ctr = ctrs.ElementAt(0);
var ctrParamsAsNull = ctr.GetParameters().Select(p => (object)null);
book ok = false;
try
{
ctr.Invoke(ctrParamsAsNull.ToArray());
}
catch(ArgumentNullException)
{
//you get exception you expected so continue
ok = true;
}
if(!ok)
{
// you didn't get exception so throw your own exception with message that contains controller type name
throw new Exception(String.Format("Ctor on type {0} did not throw ArgumentNullException",controller.Name);
}
}
}
This is only as idea to work on. You can refactor that inside your own static assertion method...