feat: add initial unit tests for user service and configure bun test script.

package.json

@@ -18,7 +18,8 @@
     "db:push:local": "drizzle-kit push",
     "dev": "bun --watch src/index.ts",
     "db:studio": "drizzle-kit studio --host 0.0.0.0",
-    "studio:remote": "bash scripts/remote-studio.sh"
+    "studio:remote": "bash scripts/remote-studio.sh",
+    "test": "bun test"
   },
   "dependencies": {
     "@napi-rs/canvas": "^0.1.84",

src/modules/user/user.service.test.ts

@@ -0,0 +1,99 @@
+
+import { describe, it, expect, mock, beforeEach, afterEach } from "bun:test";
+import { userService } from "./user.service";
+
+// Define mock functions outside so we can control them in tests
+const mockFindFirst = mock();
+const mockInsert = mock();
+const mockUpdate = mock();
+const mockDelete = mock();
+const mockValues = mock();
+const mockReturning = mock();
+const mockSet = mock();
+const mockWhere = mock();
+
+// Chainable mock setup
+mockInsert.mockReturnValue({ values: mockValues });
+mockValues.mockReturnValue({ returning: mockReturning });
+
+mockUpdate.mockReturnValue({ set: mockSet });
+mockSet.mockReturnValue({ where: mockWhere });
+mockWhere.mockReturnValue({ returning: mockReturning });
+
+
+// Mock DrizzleClient
+mock.module("@/lib/DrizzleClient", () => {
+    return {
+        DrizzleClient: {
+            query: {
+                users: {
+                    findFirst: mockFindFirst,
+                },
+            },
+            insert: mockInsert,
+            update: mockUpdate,
+            delete: mockDelete,
+            transaction: async (cb: any) => {
+                // Pass the mock client itself as the transaction object
+                // This simplifies things as we use the same structure for tx and client
+                return cb({
+                    query: {
+                        users: {
+                            findFirst: mockFindFirst,
+                        },
+                    },
+                    insert: mockInsert,
+                    update: mockUpdate,
+                    delete: mockDelete,
+                });
+            }
+        },
+    };
+});
+
+describe("userService", () => {
+    beforeEach(() => {
+        mockFindFirst.mockReset();
+        mockInsert.mockClear();
+        mockValues.mockClear();
+        mockReturning.mockClear();
+    });
+
+    describe("getUserById", () => {
+        it("should return a user when found", async () => {
+            const mockUser = { id: 123n, username: "testuser", class: null };
+            mockFindFirst.mockResolvedValue(mockUser);
+
+            const result = await userService.getUserById("123");
+
+            expect(result).toEqual(mockUser as any);
+            expect(mockFindFirst).toHaveBeenCalledTimes(1);
+        });
+
+        it("should return undefined when user not found", async () => {
+            mockFindFirst.mockResolvedValue(undefined);
+
+            const result = await userService.getUserById("999");
+
+            expect(result).toBeUndefined();
+            expect(mockFindFirst).toHaveBeenCalledTimes(1);
+        });
+    });
+
+    describe("createUser", () => {
+        it("should create and return a new user", async () => {
+            const newUser = { id: 456n, username: "newuser", classId: null };
+            mockReturning.mockResolvedValue([newUser]);
+
+            const result = await userService.createUser("456", "newuser");
+
+            expect(result).toEqual(newUser as any);
+            expect(mockInsert).toHaveBeenCalledTimes(1);
+            expect(mockValues).toHaveBeenCalledWith({
+                id: 456n,
+                username: "newuser",
+                classId: undefined
+            });
+        });
+    });
+});