Add more and unify tests for absent object cases

- Unify test data for nonexistence of an object/string and collection.
- Introduce more test through adding missing test data to existing tests.
- Improve logic for checking absence of values to match tests.
- Add missing tests for absent value validation.
- Update documentation to include shared test functionality.

src/application/Environment/BrowserOs/DetectorBuilder.ts

@@ -27,7 +27,7 @@ export class DetectorBuilder {
 
   private detect(userAgent: string): OperatingSystem {
     if (!userAgent) {
-      throw new Error('User agent is null or undefined');
+      throw new Error('missing userAgent');
     }
     if (this.existingPartsInUserAgent.some((part) => !userAgent.includes(part))) {
       return undefined;