feat: add integration test for economy transfer flow

Tests the full transfer cycle against a real database: debit/credit,
transaction records, insufficient funds rejection, self-transfer
rejection, non-positive amounts, and sequential transfers.

Uses *.integration.test.ts convention — excluded from default test
runs, included with --integration flag in CI.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

shared/modules/economy/economy.integration.test.ts

@@ -8,6 +8,10 @@ import { economyService } from "./economy.service";
 const SENDER_ID = "999000000000000001";
 const RECEIVER_ID = "999000000000000002";
 
+// This test requires a real database connection.
+// It is excluded from `bun test` by default (*.integration.test.ts pattern)
+// and only runs in CI with `--integration` flag, which provides PostgreSQL.
+
 async function cleanupTestUsers() {
     // transactions.userId has onDelete: 'cascade', so deleting users removes their transactions
     await DrizzleClient.delete(users).where(eq(users.id, BigInt(SENDER_ID)));
@@ -77,16 +81,26 @@ describe("Economy Integration Tests", () => {
             expect(receiverTxs[0]!.type).toBe("TRANSFER_IN");
         });
 
-        it("should reject a transfer when sender has insufficient funds", async () => {
+        it("should reject transfer with insufficient funds and leave balances unchanged", async () => {
             await expect(
                 economyService.transfer(SENDER_ID, RECEIVER_ID, 2000n)
             ).rejects.toThrow("Insufficient funds");
 
-            // Verify balances are unchanged
+            // Verify balances unchanged
             const sender = await DrizzleClient.query.users.findFirst({
                 where: eq(users.id, BigInt(SENDER_ID)),
             });
+            const receiver = await DrizzleClient.query.users.findFirst({
+                where: eq(users.id, BigInt(RECEIVER_ID)),
+            });
             expect(sender!.balance).toBe(1000n);
+            expect(receiver!.balance).toBe(500n);
+
+            // Verify no transaction records were created
+            const senderTxs = await DrizzleClient.query.transactions.findMany({
+                where: eq(transactions.userId, BigInt(SENDER_ID)),
+            });
+            expect(senderTxs.length).toBe(0);
         });
 
         it("should reject a self-transfer", async () => {
@@ -122,30 +136,5 @@ describe("Economy Integration Tests", () => {
             // Receiver: 500 + 100 + 200 - 50 = 750
             expect(receiver!.balance).toBe(750n);
         });
-
-        it("should roll back the entire transfer if an error occurs mid-transaction", async () => {
-            // Attempting to transfer more than balance ensures the transaction aborts
-            // after the sender check but before any SQL update is committed
-            const senderBefore = await DrizzleClient.query.users.findFirst({
-                where: eq(users.id, BigInt(SENDER_ID)),
-            });
-
-            await expect(
-                economyService.transfer(SENDER_ID, RECEIVER_ID, 9999n)
-            ).rejects.toThrow("Insufficient funds");
-
-            const senderAfter = await DrizzleClient.query.users.findFirst({
-                where: eq(users.id, BigInt(SENDER_ID)),
-            });
-
-            // Balance must be unchanged — no partial debit
-            expect(senderAfter!.balance).toBe(senderBefore!.balance);
-
-            // No transaction records should have been written
-            const senderTxs = await DrizzleClient.query.transactions.findMany({
-                where: eq(transactions.userId, BigInt(SENDER_ID)),
-            });
-            expect(senderTxs.length).toBe(0);
-        });
     });
 });