Verify number of Api calls in cypress - cypress

Question

We are using segment in our application and i need to implement an E2E test in order to verify the number of segment calls, i must be sure that every event will be called only once.
I've been searching for a while, i've found this command that verifies the number of api calls:
Cypress.Commands.add(`verifyCallCount`, (alias, expectedNumberOfCalls) => {
const resolvedAlias = alias[0] === `#` ? alias.substring(1) : alias;
cy.get(`${resolvedAlias}.all`, { timeout: 20000 }).then((calls) => {
cy.wrap(calls.length).should(`equal`, expectedNumberOfCalls);
});
});
I use this command after waiting for the api call:
cy.wait(`#${eventAlias}`, { timeout: 20000 })
.then((interception) => {
return JSON.parse(interception.request.body);
})
.then(() => cy.verifyCallCount(eventAlias, 1););
Here is also the place where i add my alias for the api call.
beforeEach(() => {
cy.intercept('POST', 'https://api.segment.io/v1', (req) => {
const body = JSON.parse(req.body);
if (body.hasOwnProperty('type') && body.type === SampleEvent) {
req.alias = eventAlias;
}
});
});
});
Using this approach, when i run the test on local environment, it passes without any problem. but the same test fails on github's actions. and this is the error:
AssertionError: Timed out retrying after 10000ms: Expected to find element: `eventAlias.all`, but never found it.
I think that the .get() command is not being executed after .wait(), i tried to change the order of the commands, but it's not helping.
How can i fix this problem in github actions?
Is there any other way to verify the number of api calls in cypress?
I appreciate any help, thank you.

Answer 1

The answer you used from here Verify number of times request was made is wrong.
The line const resolvedAlias = alias[0] === '#' ? alias.substring(1) : alias removes the initial #, but it needs to be kept.
Also the timeout in cy.get('${resolvedAlias}.all', { timeout: 20000 }) has no effect, it doesn't wait 20 seconds for all calls to happen.
In your test scenario there may be 0, 1, or 2 calls. You want to fail if there is 0 calls or 2 calls, and pass if there is exactly 1 call.
This is enough to fail if there is 0 calls
cy.wait(`#${eventAlias}`, { timeout: 20000 })
To fail if there are 2 calls, you must use a hard wait, then verify the call count
cy.wait(`#${eventAlias}`, { timeout: 20_000 })
cy.wait(2_000) // wait an interval for any extra call to occur
cy.get(`#${eventAlias}.all`)
.its('length')
.should(`equal`, 1); // if two calls happened in interval, fail here

Answer 2

I notice you mention github actions. I had similar problems when testing an API call in CI, the test runs much slower and cause flakiness.
I suggest mocking the response to get better, more consistent performance from your test.
Ref: Controlling the response
As a bonus, there is no need for any long timeout because your mock replies immediately.
beforeEach(() => {
cy.intercept('POST', 'https://api.segment.io/v1', (req) => {
const body = JSON.parse(req.body);
if (body.hasOwnProperty('type') && body.type === SampleEvent) {
req.alias = eventAlias;
// here send mock response without any network delay
req.reply({
headers: {
Set-Cookie: 'newUserName=Peter Pan;'
},
statusCode: 201,
body: {
name: 'Peter Pan'
}
})
}
});
});
})
it('tests there is only a single POST from app', () => {
cy.wait(`#${eventAlias}`)
cy.wait(100)
cy.get(`#${eventAlias}.all`).then((calls) => {
cy.wrap(calls.length).should(`equal`, 1);
});
})

Answer 3

Your goal is to ensure only 1 API call.
You will need the test to wait and see if a 2nd call occurs.
it('accurately test that only one API call happens', () => {
const numOfRequests = 1
cy.intercept('**/api/*', cy.spy().as('api-spy'))
cy.visit('/');
cy.wait(1000)
cy.get('#api-spy').its('callCount').should('equal', numOfRequests)
})
I tested with a simple page that deliberately calls twice, with a delay 100ms between calls,
<script>
fetch('api/1')
setTimeout(() => fetch('api/2'), 100) // delayed 2nd fetch we want to test for
</script>
Without the hard wait the test gives me a false pass.
I also tried inverting the logic, but it still needs a hard wait to test correctly
cy.intercept('**/api/*', cy.spy().as('api-spy'))
cy.visit('/');
cy.wait(1000)
cy.get('#api-spy').its('callCount')
.should('not.equal', 0)
.and('not.equal', 2) // false pass without hard wait
})
Counting inside the routeHandler that checks body.type
2nd alias for call count
before(() => {
cy.wrap(0).as('eventCount')
})
beforeEach(() => {
cy.intercept('POST', 'https://api.segment.io/v1', (req) => {
const body = JSON.parse(req.body);
if (body.hasOwnProperty('type') && body.type === SampleEvent) {
req.alias = eventAlias;
cy.get('#eventCount').then(count => {
cy.wrap(count + 1).as('eventCount')
})
}
});
});
});
it('checks the count', () => {
cy.visit('/');
cy.wait(1000)
cy.get('#eventCount')
.should('equal', 1)
})
Incrementing a global
let eventCount = 0;
beforeEach(() => {
cy.intercept('POST', 'https://api.segment.io/v1', (req) => {
const body = JSON.parse(req.body);
if (body.hasOwnProperty('type') && body.type === SampleEvent) {
req.alias = eventAlias;
eventCount += 1
}
});
});
});
it('checks the count', () => {
cy.visit('/');
cy.wait(1000)
.then(() => {
cy.wrap(eventCount)
.should('equal', 1)
})
})

Answer 4

When you want to get all of the alias calls, you will need to use # to signify the alias. So the custom command will need to be updated.
Cypress.Commands.add(`verifyCallCount`, (registeredAlias, expectedNumberOfCalls) => {
if(alias[0] !== '#') {
throw new Error ('alias does not start with '#')
}
cy.get(`${registeredAlias}.all`, { timeout: 20000 }).then((calls) => {
cy.wrap(calls.length).should(`equal`, expectedNumberOfCalls);
});
});
Usage
cy.intercept('call').as('call')
// some action to trigger call
cy.wait('#call')
// some other actions
cy.verifyCallCount('#call')

Answer 5

Is there any other way to verify the number of api calls in cypress?
This is a concise way to count the api calls and wait for them to finish.
You can pass a cy.spy() in as a "response" and you can use that to count the number of times the intercept was hit.
Using .should() in the Cypress assertion will wait until the expected number of requests to come back.
it('test', () => {
const numOfRequests = 5;
cy.intercept('https://api.segment.io/v1', cy.spy().as('api-spy'));
// Do something to trigger 5 requests
cy.get('#api-spy').its('callCount').should('equal', numOfRequests);
});
If there are a sequence of different endpoints you are waiting for such as /v1/login followed by a /v1/getData etc, the URL in the cy.intercept may need to use a wildcard.
For example:
cy.intercept('https://api.segment.io/v1/**')