cy.wait() non-deterministically times out when waiting for mocked responses: No response ever occurred.

Current behavior:

Sometimes, cy.wait() times out when waiting for some nth response of a mocked out endpoint, even though the Cypress UI shows that the request was stubbed out.

Desired behavior:

The documentation for cy.wait() says:

Each time we use cy.wait() for an alias, Cypress waits for the next nth matching request.

It seems that this behavior should be deterministic and the nth call to cy.wait() should find the nth response of a mocked endpoint if n responses have been successfully stubbed out.

Steps to reproduce:

1. Mock out an API response, and simulate n calls using that endpoint
2. Queue n cy.wait() calls (either by manually calling cy.wait() n times, or cy.wait([alias, alias, ..., alias])
3. This test should always pass, but sometimes the test will fail due a timeout while waiting for one of the responses

Versions

3.0.2, Mac OSX El Capitan, Chrome 67

[michaelsharpe]

I am currently experiencing a similar issue. Random tests across our test suite fail on a cy.wait, but it only happens in our CI environment, not when running things locally. I can run the same test suite three times, and of the three two fail and one passes; of the two failing, they each fail in different test suites, but both from waiting on cy.wait commands that never returned.

My current theory is that some responses are so fast that cypress doesn’t have time to hook in. The main difference from our CI environment to our local development is that the CI environment is entirely inside docker. API server, DB, static server that serves the client, and cypress. The docker network connections may be so fast on some responses that it is missed by Cypress.

That is my going theory, at least. I don’t have time to do a minimal reproduction, but I will try to make some time in the next few days. I think setting it all up inside docker-compose should make for a reproducible demonstration of the bug.

[jennifer-shehane]

There is a difference between manually calling cy.wait() n times and using cy.wait([alias, alias, ..., alias])

Each cy.wait() command has a default requestTimeout of 5000 ms and a default responseTimeout of 30000. This means:

Scenario 1

cy.wait('@alias1') // waits 30 seconds to respond
cy.wait('@alias1') // waits 30 seconds to respond 2nd time
cy.wait('@alias1') // waits 30 seconds to respond 3rd time
cy.wait('@alias1') // waits 30 seconds to respond 4th time

Scenario 2

cy.wait(['@alias1', '@alias1', '@alias1', '@alias1']) // waits 30 seconds for request to respond 4 times

I find the behavior in Scenario 2 to be incredibly confusing - as I myself had many response timeouts seemingly for no reason until I discovered this was the case. I’ve since changed nearly all of my cy.wait() to be chained, like in Scenario 1, rendering the Scenario 2 usage pretty much useless.

Proposal

In order to fix this behavior, I would ideally want the timeouts to apply to each defined alias within the array individually.

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@lawsumisu Please let me know if this is not the case and there is also a non-deterministic timeout when serially defining the cy.wait().