test: add auth service tests

Made-with: Cursor

tests/test-utils.ts

@@ -10,10 +10,52 @@ export type MockDb = {
   delete: ReturnType<NodePgDatabase<typeof schema>['delete']>;
 };
 
+/** Build a select chain that resolves to the given rows at .limit(n) */
+export function selectChain(resolveAtLimit: unknown[] = []) {
+  const limitFn = vi.fn().mockResolvedValue(resolveAtLimit);
+  return {
+    from: vi.fn().mockReturnValue({
+      where: vi.fn().mockReturnValue({
+        limit: limitFn,
+        orderBy: vi.fn().mockReturnValue({ limit: limitFn }),
+      }),
+      limit: limitFn,
+    }),
+  };
+}
+
+/** Build an insert chain that resolves at .returning() or .values() */
+export function insertChain(resolveAtReturning: unknown[] = []) {
+  const returningFn = vi.fn().mockResolvedValue(resolveAtReturning);
+  const chainFromValues = {
+    returning: returningFn,
+    then: (resolve: (v?: unknown) => void) => resolve(undefined),
+  };
+  return {
+    values: vi.fn().mockReturnValue(chainFromValues),
+    returning: returningFn,
+  };
+}
+
+/** Build an update chain that resolves at .where() */
+export function updateChain(resolveAtWhere: unknown[] = []) {
+  return {
+    set: vi.fn().mockReturnValue({
+      where: vi.fn().mockResolvedValue(resolveAtWhere),
+    }),
+  };
+}
+
+/** Build a delete chain that resolves at .where() */
+export function deleteChain() {
+  return {
+    where: vi.fn().mockResolvedValue(undefined),
+  };
+}
+
 /**
  * Create a chainable mock for Drizzle DB operations.
- * Configure chain terminals (limit, returning) to resolve to desired values.
- * Example: mockDb.select.mockReturnValue({ from: vi.fn().mockReturnValue({ where: vi.fn().mockReturnValue({ limit: vi.fn().mockResolvedValue([user]) }) }) })
+ * Use mockReturnValue with selectChain/insertChain/updateChain/deleteChain.
  */
 export function createMockDb(): MockDb {
   const chain = {