Undefined method 'factory'

When running tests I get this:

1) Tests\Feature\LoginTest::test_user_can_login_with_correct_credentials
Error: Call to undefined function Tests\Feature\factory()

The test looks like this:

public function test_user_can_login_with_correct_credentials()
    {
        $user = factory(User::class)->create([
            'password' => bcrypt($password = 'i-love-laravel'),
        ]);

        $response = $this->post('/login', [
            'email' => $user->email,
            'password' => $password,
        ]);

        $response->assertRedirect('/dashboard');
        $this->assertAuthenticatedAs($user);
    }

But this is being flagged with the error:

Undefined function 'factory'

I am using L9

Any ideas?