This repro demonstrates a bug where a cy.request to a localhost server connected to ipv4 (127.0.0.1) influences later requests, notably cy.visit. In this case, we have a backend server running on "127.0.0.1" and a front-end server running on "::1" (both can be accessed with localhost).
To replicate the bug:
- In a separate terminal run
npm run serve - In a separate terminal run
npm run server - In a separate terminal run
npx cypress open- Choose e2e testing
- Choose any browser
- Choose
app.cy.js
The first request is made to http://localhost:3333/api/login and the visit is configured to visit http://localhost:4200 via the configured baseUrl. The issue is that the frontend server is not available at http://127.0.0.1:4200 but rather http://[::1]:4200.
If the request is moved after the visit, everything works fine.
If the request is commented out and Cypress is allowed to visit successfully, commenting the request back in works fine.
Note: Cypress needs to be killed and restarted to reset the server state.
I believe the issue lives with the server first connecting to an ipv4 address due to the request (127.0.0.1) and then coercing the visit to http://localhost:4200 to http://127.0.0.1:4200.