Add direct unit tests for mergeProhibitedViolations in TransactionUtilsTest

Tests the real implementation (not mocked) to verify that showInReview
is preserved on the merged violation when at least one source violation
has showInReview: true.

Co-authored-by: Issa Nimaga <inimaga@users.noreply.github.com>

Author: MelvinBot

tests/unit/TransactionUtilsTest.ts

@@ -8,6 +8,7 @@ import ONYXKEYS from '@src/ONYXKEYS';
 import type {Attendee} from '@src/types/onyx/IOU';
 import * as TransactionUtils from '../../src/libs/TransactionUtils';
 import type {Card, Policy, Report, Transaction} from '../../src/types/onyx';
+import type {TransactionViolation} from '../../src/types/onyx/TransactionViolation';
 import createRandomPolicy, {createCategoryTaxExpenseRules} from '../utils/collections/policies';
 import {createRandomReport} from '../utils/collections/reports';
 import waitForBatchedUpdates from '../utils/waitForBatchedUpdates';
@@ -3033,6 +3034,95 @@ describe('TransactionUtils', () => {
         });
     });
 
+    describe('mergeProhibitedViolations', () => {
+        it('should preserve showInReview as true when at least one source violation has showInReview: true', () => {
+            const violations: TransactionViolation[] = [
+                {
+                    name: CONST.VIOLATIONS.PROHIBITED_EXPENSE,
+                    type: CONST.VIOLATION_TYPES.VIOLATION,
+                    data: {prohibitedExpenseRule: 'alcohol'},
+                    showInReview: true,
+                },
+                {
+                    name: CONST.VIOLATIONS.PROHIBITED_EXPENSE,
+                    type: CONST.VIOLATION_TYPES.VIOLATION,
+                    data: {prohibitedExpenseRule: 'gambling'},
+                    showInReview: false,
+                },
+                {
+                    name: CONST.VIOLATIONS.PROHIBITED_EXPENSE,
+                    type: CONST.VIOLATION_TYPES.VIOLATION,
+                    data: {prohibitedExpenseRule: 'tobacco'},
+                },
+            ];
+
+            const result = TransactionUtils.mergeProhibitedViolations(violations);
+
+            expect(result).toHaveLength(1);
+            expect(result.at(0)?.name).toBe(CONST.VIOLATIONS.PROHIBITED_EXPENSE);
+            expect(result.at(0)?.data?.prohibitedExpenseRule).toEqual(['alcohol', 'gambling', 'tobacco']);
+            expect(result.at(0)?.showInReview).toBe(true);
+        });
+
+        it('should set showInReview to false when no source violation has showInReview: true', () => {
+            const violations: TransactionViolation[] = [
+                {
+                    name: CONST.VIOLATIONS.PROHIBITED_EXPENSE,
+                    type: CONST.VIOLATION_TYPES.VIOLATION,
+                    data: {prohibitedExpenseRule: 'alcohol'},
+                    showInReview: false,
+                },
+                {
+                    name: CONST.VIOLATIONS.PROHIBITED_EXPENSE,
+                    type: CONST.VIOLATION_TYPES.VIOLATION,
+                    data: {prohibitedExpenseRule: 'gambling'},
+                },
+            ];
+
+            const result = TransactionUtils.mergeProhibitedViolations(violations);
+
+            expect(result).toHaveLength(1);
+            expect(result.at(0)?.showInReview).toBeFalsy();
+        });
+
+        it('should not modify non-prohibited violations', () => {
+            const violations: TransactionViolation[] = [
+                {
+                    name: CONST.VIOLATIONS.DUPLICATED_TRANSACTION,
+                    type: CONST.VIOLATION_TYPES.VIOLATION,
+                },
+                {
+                    name: CONST.VIOLATIONS.PROHIBITED_EXPENSE,
+                    type: CONST.VIOLATION_TYPES.VIOLATION,
+                    data: {prohibitedExpenseRule: 'alcohol'},
+                    showInReview: true,
+                },
+            ];
+
+            const result = TransactionUtils.mergeProhibitedViolations(violations);
+
+            expect(result).toHaveLength(2);
+            const duplicateViolation = result.find((v) => v.name === CONST.VIOLATIONS.DUPLICATED_TRANSACTION);
+            const prohibitedViolation = result.find((v) => v.name === CONST.VIOLATIONS.PROHIBITED_EXPENSE);
+            expect(duplicateViolation).toBeDefined();
+            expect(prohibitedViolation?.showInReview).toBe(true);
+            expect(prohibitedViolation?.data?.prohibitedExpenseRule).toEqual(['alcohol']);
+        });
+
+        it('should return violations unchanged when there are no prohibited violations', () => {
+            const violations: TransactionViolation[] = [
+                {
+                    name: CONST.VIOLATIONS.DUPLICATED_TRANSACTION,
+                    type: CONST.VIOLATION_TYPES.VIOLATION,
+                },
+            ];
+
+            const result = TransactionUtils.mergeProhibitedViolations(violations);
+
+            expect(result).toEqual(violations);
+        });
+    });
+
     describe('shouldClearConvertedAmount', () => {
         it('returns false when destinationCurrency is undefined', () => {
             const transaction = generateTransaction({currency: 'USD'});