// Unregister one
        assertTrue(mockService.unregisterWitness(reg2));
        assertEquals(2, mockService.getRegistrationCount());
        assertFalse(mockService.hasRegistration(reg2));

        // Clean up remaining
        assertTrue(mockService.unregisterWitness(reg1));
        assertTrue(mockService.unregisterWitness(reg3));
        assertEquals(0, mockService.getRegistrationCount());
    }