Add some instances for testing the filter function

src/web/app/components/question-submission-form/question-submission-form.component.spec.ts

@@ -1176,5 +1176,31 @@ describe('QuestionSubmissionFormComponent', () => {
 
     expect(component.dropdownVisible[index]).toBe(true);
   })
+
+  it('filterRecipients: should filter recipient list in the dropdown list and update dropdown visibility', ()=>{
+
+      const value = 'alex';
+      const index = 0;
+
+      component.model.recipientList = [
+        { recipientIdentifier: '0', recipientName: 'Alice Betsy' },
+        { recipientIdentifier: '1', recipientName: 'Benny Charles' },
+        { recipientIdentifier: '2', recipientName: 'Group 2 | Tutorial 13 | Alex Kim' },
+        { recipientIdentifier: '3', recipientName: 'Lecture #1 @ Room A | Jason Doe' },
+        { recipientIdentifier: '4', recipientName: 'Lab Session *10* | Annie K. & John L.' },
+        { recipientIdentifier: '5', recipientName: 'Group 3: Research Team | Dr. Alex Smith' }
+      ];
+
+      component.getSelectionOptionLabel = (recipient: any) => recipient.recipientName;
+      component.filterRecipients(value, index);
+
+      // Testing for the filtered recipients based on 'alex'
+      expect(component.filteredRecipients[index].length).toBe(2);
+      expect(component.filteredRecipients[index][0].recipientName).toBe('Group 2 | Tutorial 13 | Alex Kim');
+      expect(component.filteredRecipients[index][1].recipientName).toBe('Group 3: Research Team | Dr. Alex Smith');
+
+      // Dropdown should be visible for the filtered results
+      expect(component.dropdownVisible[index]).toBe(true);
+  });
 
 });