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/infrastructure/CodeRunner.ts

@@ -34,7 +34,7 @@ function getExecuteCommand(scriptPath: string, environment: Environment): string
     case OperatingSystem.Windows:
       return scriptPath;
     default:
-      throw Error('undefined os');
+      throw Error(`unsupported os: ${OperatingSystem[environment.os]}`);
   }
 }