add unit test for getFormattedPostedDate

tests/unit/TransactionUtilsTest.ts

@@ -63,4 +63,33 @@ describe('TransactionUtils', () => {
             });
         });
     });
+    describe('getPostedDate', () => {
+        describe('when posted date is undefined', () => {
+            const transaction = generateTransaction({
+                posted: undefined,
+            });
+
+            it('returns an empty string', () => {
+                const expectedResult = '';
+
+                const result = TransactionUtils.getFormattedPostedDate(transaction);
+
+                expect(result).toEqual(expectedResult);
+            });
+        });
+
+        describe('when posted date has value with format YYYYMMdd', () => {
+            const transaction = generateTransaction({
+                posted: '20241125',
+            });
+
+            it('returns the posted date with the correct format YYYY-MM-dd', () => {
+                const expectedResult = '2024-11-25';
+
+                const result = TransactionUtils.getFormattedPostedDate(transaction);
+
+                expect(result).toEqual(expectedResult);
+            });
+        });
+    });
 });