Installing PrimeNG 16.9.15-lts with valid license breaks Jest unit tests

[Thomas-Schindler]

After acquiring the PrimeNG LTS License for major version 16 and installing the version 16.9.15-lts, many of our unit test fail with the following error:

TypeError: linkObserver.observe is not a function
    at Object.<anonymous> (C:\Users\tschindler\workspaces\empic-med-web\node_modules\primeng\fesm2022\primeng-api.mjs:1003:30)
    at Generator.throw (<anonymous>)
    at rejected (C:\Users\tschindler\workspaces\empic-med-web\node_modules\primeng\fesm2022\primeng-api.mjs:57:29)
    at _ZoneDelegate.Object.<anonymous>._ZoneDelegate.invoke (C:\Users\tschindler\workspaces\empic-med-web\node_modules\zone.js\bundles\zone.umd.js:411:30)
    at ProxyZoneSpec.Object.<anonymous>.ProxyZoneSpec.onInvoke (C:\Users\tschindler\workspaces\empic-med-web\node_modules\zone.js\bundles\zone-testing.umd.js:300:43)
    at _ZoneDelegate.Object.<anonymous>._ZoneDelegate.invoke (C:\Users\tschindler\workspaces\empic-med-web\node_modules\zone.js\bundles\zone.umd.js:410:56)
    at Object.onInvoke (C:\Users\tschindler\workspaces\empic-med-web\node_modules\@angular\core\fesm2022\core.mjs:11083:33)
    at _ZoneDelegate.Object.<anonymous>._ZoneDelegate.invoke (C:\Users\tschindler\workspaces\empic-med-web\node_modules\zone.js\bundles\zone.umd.js:410:56)

I don't know, if there is the possibility to mock the LicenseManager for running the unit tests.

Interestingly enough, the error occurs only, when I run the whole test suite. Running the single tests, each test runs successfully:

Running the test suite:

Success of the single test:

Dependencies in my package.json file:

        "@angular/animations": "^16.2.12",
        "@angular/cdk": "^16.2.12",
        "@angular/common": "^16.2.12",
        "@angular/compiler": "^16.2.12",
        "@angular/core": "^16.2.12",
        "@angular/forms": "^16.2.12",
        "@angular/platform-browser": "^16.2.12",
        "@angular/platform-browser-dynamic": "^16.2.12",
        "@angular/router": "^16.2.12",
        "@ngneat/transloco": "^6.0.4",
        "@ngrx/component-store": "~16.3.0",
        "@ngrx/effects": "~16.3.0",
        "@ngrx/entity": "~16.3.0",
        "@ngrx/router-store": "~16.3.0",
        "@ngrx/store": "~16.3.0",
        "@nx/angular": "16.10.0",
        "@types/lodash-es": "^4.17.5",
        "@types/string-hash": "^1.1.3",
        "angular-code-input": "^2.0.0",
        "angularx-qrcode": "^16.0.1",
        "date-fns": "^2.30.0",
        "fast-xml-parser": "^4.4.1",
        "immer": "^10.1.1",
        "lodash-es": "^4.17.21",
        "npm": "^9.2.0",
        "primeflex": "^3.3.1",
        "primeicons": "^7.0.0",
        "primeng": "^16.9.15-lts",
        "rxjs": "~7.8.1",
        "tslib": "^2.2.0",
        "validator": "^13.11.0",
        "web-animations-js": "^2.3.2",
        "zone.js": "~0.13.0"
    },
    "devDependencies": {
        "@angular-devkit/build-angular": "^16.2.12",
        "@angular-devkit/core": "^16.2.12",
        "@angular-devkit/schematics": "^16.2.12",
        "@angular-eslint/eslint-plugin": "16.0.3",
        "@angular-eslint/eslint-plugin-template": "16.0.3",
        "@angular-eslint/template-parser": "16.0.3",
        "@angular/cli": "~16.2.0",
        "@angular/compiler-cli": "^16.2.12",
        "@angular/language-service": "^16.2.12",
        "@badeball/cypress-cucumber-preprocessor": "^20.0.1",
        "@bahmutov/cypress-esbuild-preprocessor": "^2.2.0",
        "@cypress/browserify-preprocessor": "^3.0.2",
        "@cypress/grep": "^3.1.3",
        "@happy-dom/jest-environment": "^13.6.2",
        "@ngrx/schematics": "~16.3.0",
        "@ngrx/store-devtools": "~16.3.0",
        "@nrwl/tao": "16.10.0",
        "@nx/cypress": "16.10.0",
        "@nx/eslint-plugin": "16.10.0",
        "@nx/jest": "16.10.0",
        "@nx/linter": "16.10.0",
        "@nx/workspace": "16.10.0",
        "@schematics/angular": "^16.2.12",
        "@types/jasmine": "~3.8.0",
        "@types/jest": "29.4.4",
        "@types/node": "14.14.33",
        "@typescript-eslint/eslint-plugin": "5.60.1",
        "@typescript-eslint/parser": "5.60.1",
        "cypress": "^13.0.0",
        "cypress-map": "^1.10.0",
        "esbuild": "0.19.2",
        "eslint": "8.46.0",
        "eslint-config-prettier": "^8.8.0",
        "eslint-plugin-cypress": "2.13.4",
        "happy-dom": "^13.6.2",
        "jasmine-core": "~3.8.0",
        "jasmine-marbles": "~0.9.1",
        "jest": "^29.7.0",
        "jest-preset-angular": "13.1.6",
        "jest-sonar-reporter": "^2.0.0",
        "jest-teamcity": "^1.11.0",
        "multiple-cucumber-html-reporter": "^3.1.0",
        "ng-packagr": "^16.2.3",
        "postcss": "^8.4.24",
        "postcss-import": "^15.1.0",
        "postcss-preset-env": "^8.5.0",
        "postcss-url": "^10.1.1",
        "prettier": "^3.3.3",
        "start-server-and-test": "^2.0.5",
        "ts-jest": "29.1.2",
        "typescript": "5.1.6"
    },

Is this a known issue which can be fixed somehow?

[Thomas-Schindler]

I found the solution for my problem by following the definition of a mock for the LinkObserver here: https://stackoverflow.com/questions/57008341/jest-testing-react-component-with-react-intersection-observer