Add unit test verifying splitExpensesTotal preserves report total on split deletion

Tests that passing correct splitExpensesTotal when deleting a split child
transaction keeps the report total unchanged, preventing the double-counting
bug that occurred when splitExpensesTotal was omitted.

Co-authored-by: Situ Chandra Shil <situchan@users.noreply.github.com>

Author: MelvinBot

tests/actions/IOUTest/SplitTest.ts

@@ -4571,6 +4571,74 @@ describe('updateSplitTransactions', () => {
         const updatedReportPreviewAction = getReportPreviewAction(chatReport?.reportID, expenseReport?.reportID);
         expect(updatedReportPreviewAction?.childVisibleActionCount).toEqual(2);
     });
+
+    it('should preserve report total when deleting a split with correct splitExpensesTotal', async () => {
+        // This tests the bug where useDeleteTransactions was not passing splitExpensesTotal,
+        // causing the report total to be incorrect after offline split deletion.
+        // Without splitExpensesTotal, changesInReportTotal = sum(remaining splits) - 0 = remaining total,
+        // which incorrectly subtracts that from the report total again.
+        const {expenseReport, originalTransactionID} = await createBaseExpense();
+        const reportID = expenseReport?.reportID ?? String(CONST.DEFAULT_NUMBER_ID);
+        const txID = originalTransactionID ?? String(CONST.DEFAULT_NUMBER_ID);
+
+        // Split into 4 parts for clean division (amount=10000, each split = 2500)
+        const splitIDs = await splitToN(4, expenseReport, txID);
+
+        // Capture the report total after the initial split
+        const reportAfterSplit = await getOnyxValue(`${ONYXKEYS.COLLECTION.REPORT}${reportID}`);
+        const totalAfterSplit = reportAfterSplit?.total ?? 0;
+
+        const {allTransactions, allReports, allReportNameValuePairs} = await getCollections();
+        const policyTags = await getPolicyTags(reportID);
+        const reports = getTransactionAndExpenseReports(reportID);
+
+        // "Delete" one split by calling updateSplitTransactions with only three remaining splits.
+        // Pass splitExpensesTotal = sum of remaining splits (this is what useDeleteTransactions now does).
+        const splitAmount = amount / 4;
+        const splitExpensesTotal = splitAmount * 3;
+
+        updateSplitTransactions({
+            allTransactionsList: allTransactions,
+            allReportsList: allReports,
+            allReportNameValuePairsList: allReportNameValuePairs,
+            transactionData: {
+                reportID,
+                originalTransactionID: txID,
+                splitExpenses: [
+                    {transactionID: splitIDs[0], amount: splitAmount, created: DateUtils.getDBTime()},
+                    {transactionID: splitIDs[1], amount: splitAmount, created: DateUtils.getDBTime()},
+                    {transactionID: splitIDs[2], amount: splitAmount, created: DateUtils.getDBTime()},
+                ],
+                splitExpensesTotal,
+            },
+            searchContext: {currentSearchHash: -2},
+            policyCategories: undefined,
+            policy: undefined,
+            policyRecentlyUsedCategories: [],
+            iouReport: expenseReport,
+            firstIOU: undefined,
+            isASAPSubmitBetaEnabled: false,
+            currentUserPersonalDetails,
+            transactionViolations: {},
+            policyRecentlyUsedCurrencies: [],
+            quickAction: undefined,
+            iouReportNextStep: undefined,
+            betas: [CONST.BETAS.ALL],
+            policyTags,
+            personalDetails: {[RORY_ACCOUNT_ID]: {accountID: RORY_ACCOUNT_ID, login: RORY_EMAIL}},
+            transactionReport: reports.transactionReport,
+            expenseReport: reports.expenseReport,
+            isOffline: false,
+        });
+        await waitForBatchedUpdates();
+
+        // With correct splitExpensesTotal: changesInReportTotal = remainingAmount - splitExpensesTotal = 0,
+        // so the report total should not change from the post-split value.
+        // Without splitExpensesTotal (the bug): changesInReportTotal = remainingAmount - 0 = remainingAmount,
+        // which would incorrectly subtract that from the total, resulting in totalAfterSplit + remainingAmount.
+        const updatedReport = await getOnyxValue(`${ONYXKEYS.COLLECTION.REPORT}${reportID}`);
+        expect(updatedReport?.total).toBe(totalAfterSplit);
+    });
 });
 
 describe('initSplitExpense', () => {