Why does Stryker JS hang when used with angular ng test?

[saranyanandagopal]

Question

Why does Stryker JS hang when used with angular ng test?

Stryker environment

"@stryker-mutator/core": "^8.6.0",
"@stryker-mutator/karma-runner": "^8.6.0"

"karma": "6.4.1",
"karma-chrome-launcher": "~3.1.0",
"karma-coverage": "^2.0.3",
"karma-coverage-istanbul-reporter": "^3.0.3",
"karma-jasmine": "5.1.0",
"karma-jasmine-html-reporter": "2.0.0",
"karma-junit-reporter": "^2.0.1",
"karma-parallel": "^0.3.1"

Additional context

When the stryker command "npx stryker run" is run, source files are instrumented, sandbox folder is created and working directory is changed to the sandbox directory. I see the below output in the terminal and nothing else happens after that. Navigating manually to the karma runner on http://localhost:9876/# shows "localhost refused to connect."

Starting Angular tests: ng test --progress=false --karma-config=C:\dev\monorepo\web.repo\node_modules@stryker-mutator\karma-runner\stryker-karma.conf.cjs --project=1-web
Starting Angular tests: ng test --progress=false --karma-config=C:\dev\monorepo\web.repo\node_modules@stryker-mutator\karma-runner\stryker-karma.conf.cjs --project=1-web

When I "cd" into the sandbox folder and run the below command manually:

ng test --progress=true --karma-config=apps/1-web/karma.conf.js --project=1-web

I see this on http://localhost:9876/#

The browser just hangs there. No console errors on the debug window either. The debug window is just blank and console shows "Skipped 0 tests"

I tried removing ngConfig->testArguments-> project and running Stryker, same result.

But if I run "ng test" in the sandbox folder, all tests are running.

My project structure: