Karma-UI5 cannot find testpage occasionally

[markus-schwarz87]

I use karma-ui5 in a CAP project to run frontend-integration-tests (OPA5). Everything is configured and the tests are executed and work. But occasionally the tests fail and I cannot find the solution for that.

Error:
31 07 2023 10:46:48.342:WARN [Chrome Headless 114.0.5735.199 (Windows 10)]: Adapter did not report total number of specs.
Chrome Headless 114.0.5735.199 (Windows 10) /base/webapp/test/integration/opaTests.qunit.html FAILED
Testpage did not define any tests.
Chrome Headless 114.0.5735.199 (Windows 10): Executed 1 of 1 (1 FAILED) (0.004 secs / 0 secs)

Maybe in 1 out 50 times the testpage(which starts the OPA5 tests) cannot be found and the log states that no tests are defined.
I already tried nearly all config options in the karma.conf which could be somehow related to that problem but the error still occurs occasionally.

Could this be a bug or do you have any suggestions?

Thanks in advance!

---

Relevant Files:

package.json

"karma-chrome-launcher": "^3",
"karma-ui5": "^3",

Karma.conf.js

process.env.CHROME_BIN = require('puppeteer').executablePath();
module.exports = function (config) {
'use strict';
config.set({
frameworks: ['ui5'],
reporters: ['progress'],
browsers: ['Chrome_custom'],
customLaunchers: {
Chrome_custom: {
base: 'ChromeHeadless',
flags: ['--window-size=1920,1080'],
},
},
singleRun: true,
ui5: {
configPath: 'ui5-mock.yaml',
testpage: 'webapp/test/testsuite.qunit.html',
failOnEmptyTestPage: true,
},
});
};

ui5-mock.yaml
specVersion: "2.6"
metadata:
name: xxxx
type: application
server:
customMiddleware:

• name: fiori-tools-proxy
  afterMiddleware: compression
  configuration:
  ignoreCertError: false # If set to true, certificate errors will be ignored. E.g. self-signed certificates will be accepted
  ui5:
  path:
  - /resources
  - /test-resources
  url: https://ui5.sap.com
• name: sap-fe-mockserver
  beforeMiddleware: csp
  configuration:
  service:
  urlPath: /xxx
  metadataPath: ./webapp/localService/metadata.xml
  mockdataPath: ./webapp/localService/data/
  generateMockData: false