Lighthouse user-flow with puppeteer not working

[kerstin97]

Hello ✋

so it's my first time using lighthouse and puppeteer and I don't understand what I'm doing wrong.
I try to test my website with a userflow (Lighthouse Userflow).

This is my code: Repository

When I run node remix_test_with_lighthouse.js, the first navigation of the flow is working. But then I get a timeout on the second flow.navigate. I've tried to disable the timeout limit with await page.setDefaultNavigationTimeout(0); but then it stucks forever.

Also if I remove the second flow.navigate, it gets stuck on the flow.timespan method.

Generally the basic test-code without lighthouse is working (node remix-test.js), so it's something with the userflow. 😢

This is the error(using node v18.15.0):

/node_modules/lighthouse/core/gather/driver/wait-for-condition.js:85
      reject(new LighthouseError(LighthouseError.errors.NO_FCP));
             ^

LighthouseError: NO_FCP
    at Timeout.<anonymous> (file:///Users/kerstinreichinger/lighthouse-puppeteer-userflows/node_modules/lighthouse/core/gather/driver/wait-for-condition.js:85:14)
    at listOnTimeout (node:internal/timers:569:17)
    at process.processTimers (node:internal/timers:512:7) {
  code: 'NO_FCP',
  friendlyMessage: 'The page did not paint any content. Please ensure you keep the browser window in the foreground during the load and try again. (NO_FCP)',
  lhrRuntimeError: true
}

Node.js v18.15.0

Thank you in advande for helping me,
Kerstin

[adamraine]

The flow.navigate method is waiting for a page navigation, but it never sees one because the page.click command does not actually initiate a real page navigation. The page is doing a "soft navigation" instead which cannot be tested with navigation mode. To audit a soft navigation right now, you need to use Lighthouse timespan mode.

We plan on adding support for auditing soft navigations in the future (#14573), but the Chrome tooling behind it is still experimental. If you're interested in being a trailblazer, you can also check out https://github.com/adamraine/lighthouse-plugin-soft-navigation.

[kerstin97]

Thank you so much for answering so quickly. Maybe after my bachelor degree I'll come back to this issue 😄