unit tests fixin

src/components/ProfileManager.test.tsx

@@ -148,7 +148,10 @@ describe('ProfileManager Authentication Flows', () => {
     render(<ProfileManager {...defaultProps} />);
 
     const signInButton = screen.getByRole('button', { name: /^sign in$/i });
-    fireEvent.click(signInButton);
+    // Using fireEvent.submit on the form is more reliable for testing form submissions
+    // and correctly handles the timing of state updates within the submit handler.
+    const form = screen.getByTestId('auth-form');
+    fireEvent.submit(form);
 
     // We need to wait for the component to re-render with the loading state.
     // The most reliable way is to wait for the visual indicator (the spinner) to appear.

src/services/db.test.ts

@@ -10,11 +10,14 @@ import { testPool } from '../tests/setup/test-db';
 // in tests use the test database.
 vi.mock('pg', async (importOriginal) => {
   const pg = await importOriginal<typeof import('pg')>();
-  // We are mocking the Pool class.
-  // The mock is a function that, when called with `new`, returns our testPool.
+  // We replace the real Pool class with a mock class.
+  // When `new Pool()` is called in the code under test, it will
+  // instantiate this mock class. The constructor of our mock
+  // immediately returns the `testPool` instance, ensuring that
+  // all database operations use the test database.
   return {
     ...pg,
-    Pool: vi.fn(() => testPool),
+    Pool: class MockPool { constructor() { return testPool; } },
   };
 });
 

src/services/shopping-list.test.ts

@@ -10,11 +10,14 @@ import bcrypt from 'bcrypt';
 // test database, resolving the circular dependency error.
 vi.mock('pg', async (importOriginal) => {
   const pg = await importOriginal<typeof import('pg')>();
-  // We are mocking the Pool class.
-  // The mock is a function that, when called with `new`, returns our testPool.
+  // We replace the real Pool class with a mock class.
+  // When `new Pool()` is called in the code under test, it will
+  // instantiate this mock class. The constructor of our mock
+  // immediately returns the `testPool` instance, ensuring that
+  // all database operations use the test database.
   return {
     ...pg,
-    Pool: vi.fn(() => testPool),
+    Pool: class MockPool { constructor() { return testPool; } },
   };
 });