t.ltime = currentTime;
        assertEquals(currentTime, t.ltime, "ltime should be mutable");
    }

    @Test
    @DisplayName("TestLocking implements Runnable")
    void testImplementsRunnable() {
        TestLocking t = new TestLocking();
        assertTrue(t instanceof Runnable, "TestLocking should implement Runnable");
    }

    @Test
    @DisplayName("run method handles null URL gracefully")