assertFalse(item1.equals("word"));

        // Symmetry
        assertTrue(item1.equals(item2));
        assertTrue(item2.equals(item1));
    }

    @Test
    public void test_equals_withNullInput() {
        // Test equals with null input - should not throw, uses null-safe comparison
        ProtwordsItem item1 = new ProtwordsItem(1, null);
        ProtwordsItem item2 = new ProtwordsItem(2, null);

        item2.setNewInput("different");

        // Should still be equal based on original input
        assertTrue(item1.equals(item2));
    }

    @Test
    public void test_equals_withNullInput() {
        // Test equals with null input - should not throw, uses null-safe comparison
        StopwordsItem item1 = new StopwordsItem(1, null);
        StopwordsItem item2 = new StopwordsItem(2, null);

Shinsuke Sugaya <******@****.***> 1773442886 +0900