How can we do callback on success and failue cases for below lines of code for test coverage using jest
const handleService = () => {
window.domain.service("1321",'',onSuccess, onFailure)
}
const onSuccess = () => {
....update state values
}
const onFailure = () => {
....update state values
}
Something like this:
Spy on window.domain.service to gain access to the calls it receives. This will allow you to access the parameters of those calls which will be "1321",'',onSuccess, onFailure
Assign the function you wish to test to a variable
Invoke the function to execute the code in it (this will get you the coverage)
(Optional) assert that the callback functions behave correctly
Here is a snippet to help demonstrate
it('should run', () => {
// Some setup to create the function on the window, may not be needed if done elsewhere.
// Could be good to do this in a beforeEach and clean up in afterEach to avoid contaminating the window object
window.domain = {
service: () => {},
}
// Spy on the window.domain.service method.
// Provide a mock implementation if you don't want the real one to be called
const serviceSpy = jest.spyOn(window.domain, 'service');
executeYourCode();
// capture the arguments to the call
const [_arg1, _arg2, onSuccess, onFailure] = serviceSpy.mock.calls[0];
// execute the callbacks
onSuccess();
onFailure();
});
Related
I am stuck on this for few days now.
while testing my handler function I would like to "fake" the call to rotateApiKeys fonction I was thinking to use stubs to achieve that.
But first I would like to see if at least I could spy on rotateApiKeys while calling the handler, so far I am getting:
AssertError: expected rotateApiKeys to be called once but was called 0 times and I can see that function actually been called.
Questions:
What would you recommend me to use? Mock/Stub/Spy
If Spy should work, why I am getting that assertError?
Handler:
async function handler(event) {
// declare a new JSON object
let handlerObject = {
"event": event,
"isValidEvent": rotateFunctions.validateEvent(event),
"actionCountObject": {}
};
if (handlerObject.isValidEvent) {
// continue here
handlerObject.actionCountObject = await rotateApiKeys(event);
}
// console log JSON handlerObject
console.log("handlerObject: " + JSON.stringify(handlerObject));
// return the object
return handlerObject;
}
unit test code:
it("Should call rotate", async function() {
var rotate = sinon.spy(rotateApiKeys, 'rotateApiKeys');
const result = await rotateApiKeys.handler(event);
rotate.restore();
sinon.assert.calledOnce(rotate);
});
I am mocking navigator functions for simple clipboard functionality. Here is the relevant code:
// FUNCTION
/**
* Adds a click event to the button which will save a string to the navigator clipboard. Checks for
* clipboard permissions before copying.
*/
function loader(): void {
async function copyUrl(): Promise<void> {
const permission = await navigator.permissions.query({ name: "clipboard-write" });
if (permission.state == "granted" || permission.state == "prompt" ) {
await navigator.clipboard.writeText("the url");
} else {
console.error('Permission not supported');
}
}
const button = document.querySelector('button') as HTMLElement;
button.addEventListener('click', async () => {
await copyUrl();
});
}
// TEST
it('works', () => {
// mock navigator functions
Object.assign(navigator, {
permissions: {
query: jest.fn(async () => ({ state: "granted" }))
},
clipboard: {
writeText: jest.fn(async () => {})
}
});
// initialize DOM
document.body.innerHTML = '<button></button>';
loader(); // adds the event listener
// click the button!
const button = document.querySelector('button') as HTMLElement;
button.click();
expect(navigator.permissions.query).toHaveBeenCalledTimes(1);
expect(navigator.clipboard.writeText).toHaveBeenCalledWith('the url');
});
The test fails on expect(navigator.clipboard.writeText).toHaveBeenCalledWith('the url') with:
Expected: "the url" Number of calls: 0
Defeats the purpose of permissions, yes, but for the sake of debugging:
Try adding a clipboard call before permissions call like so?
// FUNCTION
// ...
async function copyUrl(): Promise<void> {
// add this
await navigator.clipboard.writeText('the url');
// keep the rest still
const permission = await navigator.permissions.query({ name: "clipboard-write" });
// ...
}
This fails on the first assertion now, expect(navigator.permissions.query).toHaveBeenCalledTimes(1) with
Expected number of calls: 1 Received number of calls: 0
With the addition above, I also changed the assertions to be:
expect(navigator.clipboard.writeText).toHaveBeenCalledWith('the url');
expect(navigator.clipboard.writeText).toHaveBeenCalledTimes(2);
expect(navigator.permissions.query).toHaveBeenCalledTimes(1);
... which failed on the second assertion because it expected 2 calls but only received 1.
I have been testing in a VSCode devcontainer and tried out the extension firsttris.vscode-jest-runner to debug the test. With breakpoints in the loader function, I'm able to see that every single line executes perfectly with my mockup but still fails at the end of debug.
I even changed the mock navigator.permissions.query function to return { state: 'denied' } instead. Both running and debugging, it did not satisfy the permission check and gave an error to the console as expected but the test still failed at expect(navigator.permissions.query).toHaveBeenCalledTimes(1) (with the added writeText call before it).
It seems to me that after the first call of a mock function, the others just don't work.
Am I missing something? Send help pls lol
EDITS
Using jest.spyOn as in this answer has the same issues.
Using an async test with an expect.assertions(n) assertion still produces the exact same issue.
I am new to react-testing-library and I have been trying to test one function for a long time.
for example, I want to check if when a button is clicked a given function is called and it's throwing errors. so any help would be highly appreciated and if possible share with me any helpful resources.
signin.js
export default class SignIn extends Component {
constructor(props) {
super(props);
this.state = {
};
}
handleClose = (event, reason) => { };
validate = () => { };
change = (e) => { };
onSubmit = (e) => { };
render() {
return (<div>...</div>);
}
}
Full: https://github.com/blaise82/react-testing-library-try/blob/master/src/views/SignIn.js
this is my test
it('should submit form', async () => {
const { getByLabelText, getByText, container, debug } = render(<SignIn />);
const change = jest.fn();
const onSubmit = jest.fn();
const email = getByLabelText('email');
const password = getByLabelText('password');
const submit = getByLabelText('submit');
userEvent.type(email, 'octopusbn#gmail.com');
expect(email.value).toBe('octopusbn#gmail.com');
expect(password.value).toBe('');
expect(change).toHaveBeenCalled();
console.log(password)
await userEvent.click(submit);
expect(onSubmit).toHaveBeenCalled();
});
Full: https://github.com/blaise82/react-testing-library-try/blob/master/src/test/signin.test.js
results
> Expected number of calls: >= 1
> Received number of calls: 0
please let know what I am doing wrong.
Full code on GitHub: https://github.com/blaise82/react-testing-library-try
You can test a function by mocking all that is coming from outside of the component (aka dependencies) like - a prop callback, an external library api etc.
Before starting, let's go through what all functions are in the component.
Going through the component, I can list them as below:
Event handlers on elements [like handleClose, onSubmit, change in the component]
Functions internal to the component which do not interact with the state/functions outside the component [validate]
prop functions/library apis being called [axios.post]
Let's discuss them one by one --
Event handlers &
Functions internal to component not interacting with state/functions outside of the component
==> Event handlers that are attached to elements can safely be expected to get called. You don't need to test them if they are called. Rather, what you should test is the after-effect of them being called. Also the functions like validate
Let's take example of the change function that you are trying to test. This function after being called sets the state and the state gets reflected into the form elements. We can assert values of the form elements with a helper like this.
prop functions/library apis being called [axios.post]
==> These functions can be mocked and tested for the number of calls/parameters they are called with.
https://jestjs.io/docs/en/mock-functions.html#mocking-modules
In addition to the snippet of mocking jest as given in the link above, in your case -
axios.post.toHaveBeenCalledWith(expectedParms);
Also you can make it return results/errors you want and test respective component behaviour.
Hope you find this helpful. Cheers!
I think this is because you are not actually passing in your mocked functions to the component. You're just instantiating two constants that happen to have the name of the functions you're trying to watch, but are not actually being used anywhere in your component.
It sounds like you want to spy on your component's internal functions to see that they've been called.
Here's something of an example (not tested) based on a post (linked below) that might help you.
describe('spying on "onSubmit" method', () => {
it('should call onSubmit when the button is clicked', () => {
const wrapper = shallow(<SignIn />);
const instance = wrapper.instance();
jest.spyOn(instance, 'onSubmit');
wrapper.find('button').simulate('click');
expect(instance.onSubmit).toHaveBeenCalled();
});
});
Post: https://bambielli.com/til/2018-03-04-directly-test-react-component-methods/#spying-on-incrementcounter
I'm just getting into unit testing for the first time. Using Mocha in Node as the testing framework. All the examples I've come across create variables inside the it(). Does it matter if they are created inside or outside of it()? For example, if I have multiple it()s inside a describe(), and I need the same mocked data across all of the it()s. I'd rather not re-create the same variable repeatedly, if possible.
describe ('MyClass', function () {
let myObj = new MyObj // Mock data here
it ('Should be...', function () {
....
})
it ('Should be...', function () {
....
})
...
})
It's totally acceptable to have variables live outside of your individual it blocks, but it may not be appropriate depending on your use case.
For objects that you do not expect to change, Object.freeze is an option: const myObj = Object.freeze(new MyObj).
If you expect your tests to change your object, you should use beforeEach to ensure that they are restored to the proper state; this will prevent your it blocks from polluting one another and avoid an unpleasant debugging journey.
For example:
describe('MyClass', function () {
let myObj
beforEach(() => {
myObj = new MyObj()
})
it('changes myObj', () => {
changeProp(myObj.sum)
expect(myObj.sum).toEqual(4)
})
it('depends on myObj being the same', () => {
expect(myObj.sum).toEqual(2)
})
})
Alternately, you can eschew the fat arrow syntax and rely on the shared context between blocks in mocha:
beforeEach(function () {
this.myObj = new MyObj()
})
it('changes myObj', function () {
addTwo(this.myObj.sum)
expect(this.myObj.sum).toEqual(4)
})
it('depends on myObj being the same', function () {
expect(this.myObj.sum).toEqual(2)
})
I'm trying to create mocha tests for my controllers using a config that has to be loaded async. Below is my code. However, when the mocha test is run, it doesn't run any tests, displaying 0 passing. The console.logs are never even called. I tried doing before(next => config.build().then(next)) inside of the describe, but even though the tests run, before is never called. Is there a way to have the config be loaded one time before any tests are run?
'use strict';
const common = require('./common');
const config = require('../config');
config
.build()
.then(test);
function test() {
console.log(1);
describe('Unit Testing', () => {
console.log(2);
require('./auth');
});
}
You should run Mocha with the --delay option, and then use run() once you are done building your test suite. Here is an example derived from the code you show in the question:
'use strict';
function test() {
console.log(1);
describe('Unit Testing', () => {
console.log(2);
it("test", () => {
console.log(3);
});
});
// You must use --delay for `run()` to be available to you.
run();
}
setTimeout(test, 1000);
I'm using setTimeout to simulate an asynchronous operation. Using --delay and run() allows you to build a suite that is the result of an asynchronous computation. Note, however, that the suite must be built in one shot. (You cannot have an asynchronous process inside describe that will make calls to it. This won't work.)
One thing you should definitely not do is what rob3c suggests: calling describe or it (or both) from inside a hook. This is a mistake that every now and then people make so it is worth addressing in details. The problem is that it is just not supported by Mocha, and therefore there are no established semantics associated with calling describe or it from inside a hook. Oh, it is possible to write simple examples that work as one might expect but:
When the suite becomes more complex, the suite's behavior no longer corresponds to anything sensible.
Since there are no semantics associated with this approach, newer Mocha releases may handle the erroneous usage differently and break your suite.
Consider this simple example:
const assert = require("assert");
const p = Promise.resolve(["foo", "bar", "baz"]);
describe("top", () => {
let flag;
before(() => {
flag = true;
return p.then((names) => {
describe("embedded", () => {
for (const name of names) {
it(name, () => {
assert(flag);
});
}
});
});
});
after(() => {
flag = false;
});
it("regular test", () => {
assert(flag);
});
});
When we run it, we get:
top
✓ regular test
embedded
1) foo
2) bar
3) baz
1 passing (32ms)
3 failing
// [stack traces omitted for brevity]
What's going on here? Shouldn't all the tests pass? We set flag to true in the before hook for the top describe. All tests we create in it should see flag as true, no? The clue is in the output above: when we create tests inside a hook, Mocha will put the tests somewhere but it may not be in a location that reflects the structure of the describe blocks in the code. What happens in this case is that Mocha just appends the tests created in the hook the the very end of the suite, outside the top describe, so the after hook runs before the dynamically created tests, and we get a counter-intuitive result.
Using --delay and run(), we can write a suite that behaves in a way concordant with intuition:
const assert = require("assert");
const p = Promise.resolve(["foo", "bar", "baz"]).then((names) => {
describe("top", () => {
let flag;
before(() => {
flag = true;
});
after(() => {
flag = false;
});
describe("embedded", () => {
for (const name of names) {
it(name, () => {
assert(flag);
});
}
});
it("regular test", () => {
assert(flag);
});
});
run();
});
Output:
top
✓ regular test
embedded
✓ foo
✓ bar
✓ baz
4 passing (19ms)
In modern environments, you can use top-level await to fetch your data up front. This is a documented approach for mocha: https://mochajs.org/#dynamically-generating-tests
Slightly adapting the example from the mocha docs to show the general idea:
function fetchData() {
return new Promise((resolve) => setTimeout(resolve, 5000, [1, 2, 3]));
}
// top-level await: Node >= v14.8.0 with ESM test file
const data = await fetchData();
describe("dynamic tests", function () {
data.forEach((value) => {
it(`can use async data: ${value}`, function () {
// do something with data here
});
});
});
This is nice as it is on a per-file basis, and doesn't involve you taking on management responsibility of the test runner as you do with --delay.
The problem with using the --delay command line flag and run() callback that #Louis mentioned in his accepted answer, is that run() is a single global hook that delays the root test suite. Therefore, you have to build them all at once (as he mentioned), which can make organizing tests a hassle (to say the least).
However, I prefer to avoid magic flags whenever possible, and I certainly don't want to have to manage my entire test suite in a single global run() callback. Fortunately, there's a way to dynamically create the tests on a per-file basis, and it doesn't require any special flags, either :-)
To dynamically create It() tests in any test source file using data obtained asynchronously, you can (ab)use the before() hook with a placeholder It() test to ensure mocha waits until before() is run. Here's the example from my answer to a related question, for convenience:
before(function () {
console.log('Let the abuse begin...');
return promiseFn().
then(function (testSuite) {
describe('here are some dynamic It() tests', function () {
testSuite.specs.forEach(function (spec) {
it(spec.description, function () {
var actualResult = runMyTest(spec);
assert.equal(actualResult, spec.expectedResult);
});
});
});
});
});
it('This is a required placeholder to allow before() to work', function () {
console.log('Mocha should not require this hack IMHO');
});