assertEquals(1, chain.updateCallCount);
        assertEquals(user, chain.lastUpdatedUser);
    }

    // Test insert with multiple chains
    @Test
    public void test_insert_multipleChains() {
        User user = createTestUser("testuser");
        TestAuthenticationChain chain1 = new TestAuthenticationChain();
        TestAuthenticationChain chain2 = new TestAuthenticationChain();