test(settings): add unit test for the settings validator assertString function for test cases that should throw an error

src/features/settings/utils/__tests__/settingsValidator.test.js

@@ -14,7 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import { describe } from 'vitest';
+import { describe, test, expect } from 'vitest';
+import { assertString } from '../settingsValidator';
 
 describe('validateSettingsConfig', () => {
 
@@ -33,5 +34,18 @@ describe('assertType', () => {
 });
 
 describe('assertString', () => {
+    test.for([
+        [0],
+        [1],
+        [42],
+        [-1],
+        [-42],
 
+        [''],
+        [' '],
+        ['  '],
+        ['     ']
+    ])('throws error for the value %s', ([ value ]) => {
+        expect(() => assertString(value)).throws(Error);
+    });
 });

src/features/settings/utils/settingsValidator.js

@@ -16,7 +16,7 @@ limitations under the License.
 
 const VALID_TYPES = ['bool', 'number', 'string', 'selection', 'section'];
 
-function assertString(value, path) {
+export const assertString = function assertString (value, path) {
     if (typeof value !== 'string' || value.trim() === '') {
         throw new Error(`[settings] "${path}" must be a non-empty string`);
     }