Description
What you were expecting:
Cypress tests should run cleanly, without throwing errors related to ResizeObserver. Right now, we’re relying on a workaround that just suppresses these errors, but ideally, we’d have a proper mock in place to handle the behavior correctly.
What happened instead:
When running tests in Cypress, we’re seeing the error:
“ResizeObserver loop completed with undelivered notifications.”
To get around it, we’ve added a handler in cypress/support/index.js that catches and ignores the error using Cypress.on('uncaught:exception'). While this avoids test failures, it’s not a long-term fix and could mask real issues.
Steps to reproduce:
Run any test that uses components which trigger resize events (e.g., list.cy.js or edit.cy.js)
Open the Cypress test runner and look at the console output
Notice the ResizeObserver-related warning appearing but being caught and ignored
Related code:
Here’s the current workaround in cypress/support/index.js:
js
Copy
Edit
Cypress.on('uncaught:exception', err => {
if (
err.message.includes(
'ResizeObserver loop completed with undelivered notifications'
)
) {
return false;
}
});
Other information:
This is tied to known Cypress issues:
Ignoring the error avoids failing tests but isn't reliable or ideal
The better approach would be to mock ResizeObserver behavior properly
I’ve put together a working mock and plan to submit a PR with the fix soon
Environment:
React-admin version: [current version from package.json]
React version: [current version from package.json]
Browser: Chrome (via Cypress)
Stack trace:
ResizeObserver loop completed with undelivered notifications