I am having problems loading filenames into jest.each asynchronously.
My code:
let files: string[][]
function getFilesWorking() {
files = [["test1"], ["test2"]]
}
async function getFilesAsync() {
files = await Promise.resolve([["test1"], ["test2"]])
}
beforeAll(() => {
console.log("before")
})
describe.only("Name of the group", () => {
getFilesAsync()
test.each(files)("runs", f => {})
})
beforeAll is executed before each test but NOT before initialization of test.each, so I end up with undefined.
How can I load files before using test.each?
You can pass an async callback to beforeAll and await getFilesAsync within it
beforeAll(async () => {
await getFilesAsync();
})
As of Jest 28.1.3 and prior, this is not possible. There is an open issue documenting this behavior.
The best thing you can do for now is put your tests in a regular it() test and do a deep value comparison:
it('tests an array of cases', async () => {
const data = await getSomeAsyncData()
const expectedData = [ ... ]
expect(data).toEqual(expectedData)
})
You can use beforeEach to set up code that will run prior to tests for any given scope, https://jestjs.io/docs/setup-teardown:
beforeEach(() => {
console.log('before every test');
});
describe.only(('Name of the group') => {
beforeEach(() => {
console.log('before tests in this describe block');
})
})
Jest is only going to run the tests in your describe.only block. If you want to use beforeEach in other blocks and run those tests as well, change describe.only to describe.
(Edit: I know this is a year late, I'm just trying to look for a similar problem/solution set and thought I could answer this.)
Related
I'm trying to test a component that loads data asynchronously when mounted. The component works as expected, it's just the test that's giving me issues. The component's async loadData() function hangs at await axios.get() while jest test runner is in the component.vm.$nextTick(). As a result, the checks in the $nextTick loop never pass.
Immediately after the $nextTick loop times out, the component's await statement completes and the component renders itself. axios is mocked, so it should resolve really fast. If I remove the await and just fill in a constant instead, the entire thing executes as expected.
I'm guessing that $nextTick loop is not asynchronous and it's consuming the thread, even though this is the recommended way of testing asynchronous stuff. The problem is, I don't have an onclick async handler to await: this method is called from onMount.
Unfortunately, I don't know how to make a jsFiddle of this one, so I hope this will be enough:
my component (the relevant parts)
export default {
data() { return { content: '' }; },
mounted() { this.loadDoc() }
methods: {
async loadDoc() {
const res = await axios.get('some url'); // <-- this is the line that hangs until timeout
// const res = { data: 'test data'}; // this would test just fine
this.content = res.data;
}
}
}
and my component.spec.js:
jest.mock('axios', () => ({
get: async (url) => {
return { data: 'test data' };
}
};
describe('my super test', () => {
it('renders', (done) => {
const doc = shallowMount(myComponent);
doc.vm.$nextTick(() => {
expect(doc.html()).toContain('test data'); // <-- this never matches
done();
});
});
});
I would delete, but I just spent quite some hours for something that was suggested in the docs, but not explained that it's the only way... I'm hoping somebody else finds this useful.
Using flush-promises package instead of $nextTick loop immediately "fixed" the problem
Code sample (rework of above):
describe('my super test', () => {
it('renders', async() => {
const doc = shallowMount(myComponent);
await flushPromises();
expect(doc.html()).toContain('test data'); // <-- now it works
});
});
Every test I made with jest it's begining with await app.transaction(async(trx) => { and ends with ..rollback..
await app.transaction(async(trx) => {
const a = await update();
expect(a).toBe(something);
await trx.rollback();
});
The actual test is:
const a = await update();
expect(a).toBe(something);
And I want instead of write this wrapper for every test function, just to write within the beforeEach and afterEach.
Since the test is inside of the parameter to transaction you can't really do this in a beforeEach since it will differ based on the test. However you can avoid duplicating the code in each test by writing a helper function like this:
async function wrapper(testFn) {
return app.transaction(async(trx) => {
await testFn();
return trx.rollback();
}
}
// then do this in each test:
it('should work', () => {
await wrapper(async () => {
const a = await update();
expect(a).toBe(something);
});
});
I'm having a bit of trouble unmocking a function.
I first mock it and now I can't unmock it
//myClass.js
class myClass {
static check(v1,v2) {
return v1 > v2;
}
static async getinfo(v1,v2) {
if (this.check(v1,v2)) {
return await get('api.google.com');
}
return [];
}
}
//myclass.spec.js
describe('Testing myClass', () => {
describe('testing processing', () => {
it('should return result', () => {
const mockPatch = jest.fn().mockImplementation((version, solution) => false);
myClass.check = mockCheck;
try {
const result = await myClass.getinfo(1,2);
expect(result).toBe.([]);
}catch(e) {
throw e;
}
})
})
describe('Testing check', () => {
it('should return true', () => {
expect(myClass.check(2,1)).toBe.true
})
})
})
I already try with
myClass.check.mockRestore()
beforeEach(() => {myClass.check.mockRestore()})
jest.unmock('./myClass.js)
Is there anyway I can solve this? I read all the jest doc and i couldn't find anything
Methods should never be mocked by reassigning them, there is no way how Jest could restore their original implementation this way.
This should always be done with spyOn:
jest.spyOn(myClass, 'check').mockReturnValue(false)
This way a method can be restored with restoreMock or restoreAllMocks. This should be preferably enabled globally in Jest configuration.
I'm assuming that what you're hoping to do is to mock an implementation for use in a specific test, but then have your other tests function without the mocking.
If so, I think you could use the module mocking strategy in conjunction with mockReturnValueOnce.
Be sure to import your module at the top of your tests, then to call jest.mock with the same path. After that, you should be able to call myClass.check.mockReturnValueOnce, and it will be mocked until the next time it is called. After that, it will function normally 👍
Using nock, is there a way to disable a single nock scope?
I've been struggling with some tests that set up nocks of the same URL as some other tests. They both run fine separately, but when run in the same mocha session one of them fails, because I'm unable to re-nock the active nock scopes, meaning the nocks that were set up catches all the requests.
What I've tried:
If I set up some nocks in before() and then call scope.persist(false) in my after(), it only "unpersists" the scope, so that it's active for one more request. It does not immediately disable it.
I've found that nock.cleanAll() immediately disables the nocks so that they can be set up again, but then it also disables any global nocks that may have been set up once, common to all test cases.
So far, the only solutions I've found are 1) use unique URL:s for all nocks, which isn't always possible or 2) use nock.cleanAll() and don't rely on any global nocks - instead make sure to only set up nocks in local before() functions, including setting up the global ones repeatedly for every test that needs them.
It seems it would be highly useful to be able to do
scope = nock('http://somewhere.com').persist().get('/'.reply(200, 'foo');
and then use that nock in a bunch of tests, and finally do
scope.remove();
However, I've not been able to do something like this. Is it possible?
Example:
before(async () => {
nock('http://common').persist().get('/').reply(200, 'common');
});
after(async () => {
});
describe('Foo tests', () => {
let scope;
before(async () => {
scope = nock('http://mocked').persist().get('/').reply(200, 'foo');
});
after(() => {
// scope.persist(false); // This causes the Bar tests to use the Foo nocks one more time :(
// nock.cleanAll(); // This also disables the common nocks
});
it('Should get FOO', async () => {
expect(await fetch('http://mocked').then(res => res.text())).to.equal('foo');
expect(await fetch('http://common').then(res => res.text())).to.equal('common');
});
it('Should get FOO again', async () => {
expect(await fetch('http://mocked').then(res => res.text())).to.equal('foo');
expect(await fetch('http://common').then(res => res.text())).to.equal('common');
});
});
describe('Bar tests', () => {
let scope;
before(async () => {
scope = nock('http://mocked').persist().get('/').reply(200, 'bar');
});
after(() => {
// scope.persist(false);
// nock.cleanAll();
});
it('Should get BAR', async () => {
expect(await fetch('http://mocked').then(res => res.text())).to.equal('bar');
expect(await fetch('http://common').then(res => res.text())).to.equal('common');
});
it('Should get BAR again', async () => {
expect(await fetch('http://mocked').then(res => res.text())).to.equal('bar');
expect(await fetch('http://common').then(res => res.text())).to.equal('common');
});
});
These tests either fail the 3rd test if using scope.persist(false) (since that test still gets the foo version), or fails tests 3 and 4 if using nock.cleanAll(), since the common nocks are then removed.
I also had this issue and found a way to work around it by listening to the request event emitted by the scope and removing the interceptor when the event is fired. Ideally, I think you should be listening to the replied event but for some reason, that event wasn't firing when I tried it, not sure why. But the code below worked for me:
/**
* #jest-environment node
*/
const nock = require('nock');
describe('Test suite', () => {
test('Test case', async () => {
let interceptor1 = nock('https://example-url.com', {
reqHeaders: {
'Content-Type': 'text/xml',
soapaction: 'http://www.sample.com/servie/getOrders',
},
})
.post('/');
let interceptor2 = nock('https://example-url.com', {
reqHeaders: {
soapaction: 'http://www.sample.com/servie/getProducts',
},
})
.post('/');
let scope = interceptor1.replyWithFile(200, path.join(__dirname, './path1.xml'));
interceptor2.replyWithFile(200, path.join(__dirname, './path.xml'));
scope.on('request', (req, interceptor) => {
nock.removeInterceptor(interceptor1);
});
const resp = await asynccall();
expect(resp).toStrictEqual(exp);
});
});
As described here: Unable to remove interceptors using nock I found a way of not storing the interceptors by just setting the mock again (which apparently returns the interceptor again) and then using the returned interceptor in the removeInterceptor() function. This returns true indeed and does work in my tests.
I found a pretty simple workaround for this one - the scope has a property called "interceptors", which is an array of the various interceptors the scope uses. You can replace the "body" property of the interceptor with whatever you want.
let scope = nock(base).get(path).reply(200, []).persist();
testable.call(path).then(console.log); //returns []
scope.interceptors[0].body = [1,2,3];
testable.call(path).then(console.log); //returns [1,2,3]
I have simplified the example to be able to explain it well. I have an array which I want to iterate on. For each element of the array I want to execute a test with async/await functions, so I have this code:
const chai = require('chai');
const expect = chai.expect;
describe('Each film', async() => {
await Promise.all([1, 2, 3].map(async(n) => {
await new Promise(resolve => setTimeout(() => resolve(), 1000));
console.log('N:', n);
it('test', async() => {
expect(true).to.be.true;
});
}));
});
Executing this results in the following output:
0 passing (1ms)
N: 1
N: 2
N: 3
However, if I don't use async/await it is executed as I would expect, so it generates three tests that are resolved correctly.
What could be happening here?
UPDATE
I finally discovered that setTimeout can be used to load data asynchronously and then generate tests dinamically. This is the explanation from mocha page:
If you need to perform asynchronous operations before any of your suites are run, you may delay the root suite. Run mocha with the --delay flag. This will attach a special callback function, run(), to the global context:
So I finally wrote the code this way:
const chai = require('chai');
const expect = chai.expect;
setTimeout(async() => {
await Promise.all([1, 2, 3].map(async(n) => {
describe(`Element number ${n}`, () => {
it('test', async() => {
await new Promise(resolve => setTimeout(() => resolve(), 1000));
expect(true).to.be.true;
});
});
}));
run();
}, 500);
which generates the following output:
➜ node_modules/.bin/mocha --delay test.js
Element number 1
✓ test (1005ms)
Element number 2
✓ test (1001ms)
Element number 3
✓ test (1002ms)
3 passing (3s)
Mocha does not support asynchronous describe functions. You can generate tests dynamically, as described here, but that generation must still be synchronous.
Any tests that aren't created synchronously won't be picked up by the runner. Hence the 0 passing line at the top of your output. Mocha has decided there are no tests well before your promise resolves.
This isn't to say testing your stuff is impossible, just that you need to rethink how you're using Mocha to test it. The following, for example, would be similar to loading all of your things up front and making an assertion on each one in various tests:
const chai = require('chai');
const expect = chai.expect;
describe('Each item', () => {
let items;
before(async () => {
items = [];
await Promise.all([1, 2, 3].map(async(n) => {
await new Promise(resolve => setTimeout(() => resolve(), 1000));
items.push(n);
}));
})
it('is a number', () => {
for (item of items) {
expect(item).to.be.a('number');
}
});
it('is an integer', () => {
for (item of items) {
expect(item % 1).to.equal(0)
}
});
it('is between 1 and 3', () => {
for (item of items) {
expect(item).to.be.within(1, 3)
}
});
});
Unfortunately you won't be able to make a fully separate test displaying in your output for each item. If you want this, you may check out another test runner. I don't really have enough experience with others to say whether or not any of them support this. I'd be surprised if they do, though, since it's quite unusual.