@SuppressWarnings({
    "SelfEquals", // TODO(cpovirk): Consider using EqualsTester from Guava.
    "UndefinedEquals", // Comparisons of an object to itself *are* defined.
  })
  public void testEquals_self() {
    assertTrue("An Object should be equal to itself.", collection.equals(collection));
  }

  // Comparisons to null *are* defined.
  @SuppressWarnings("UndefinedEquals")
  public void testEquals_null() {

  @SuppressWarnings({
    "SelfEquals", // TODO(cpovirk): Consider using EqualsTester from Guava.
    "UndefinedEquals", // Comparisons of an object to itself *are* defined.
  })
  public void testEquals_self() {
    assertTrue("An Object should be equal to itself.", collection.equals(collection));
  }

  // Comparisons to null *are* defined.
  @SuppressWarnings("UndefinedEquals")
  public void testEquals_null() {

        void testEquals() {
            assertEquals(data1, data2);
            assertEquals(data2, data1);
        }

        @Test
        @DisplayName("Should be equal to itself")
        void testEqualsSelf() {
            assertEquals(data1, data1);
        }

        @Test
        @DisplayName("Should have same hashCode for equal objects")
        void testHashCodeConsistency() {

        void testNotEqualsDifferentType() {
            assertFalse(testMessage.equals("not a message"));
        }

        @Test
        @DisplayName("Should be equal to itself")
        void testEqualsSelf() {
            testMessage.setMid(12345L);
            assertTrue(testMessage.equals(testMessage));
        }
    }

    @Nested
    @DisplayName("ToString Tests")
    class ToStringTests {