@Test
  public void isTypeConvertibleShouldDelegateToIsAssignableFromMethodForNonWrappedTypesAndNullSourceType() {
    // Special classes (Enum, Object, Class, Interface) and srcType as null.
    assertThat(TypeUtils.isTypeConvertible(null, Enum.class)).isTrue();
    assertThat(TypeUtils.isAssignableFrom(Enum.class, Object.class)).isTrue();

    assertThat(TypeUtils.isTypeConvertible(null, Object.class)).isTrue();
    assertThat(TypeUtils.isAssignableFrom(Object.class, Object.class)).isTrue();

    assertThat(TypeUtils.isTypeConvertible(null, Class.class)).isTrue();
    assertThat(TypeUtils.isAssignableFrom(Class.class, Object.class)).isTrue();

    assertThat(TypeUtils.isTypeConvertible(null, TimeUnit.class)).isTrue();
    assertThat(TypeUtils.isAssignableFrom(TimeUnit.class, Object.class)).isTrue();

    assertThat(TypeUtils.isTypeConvertible(null, Serializable.class)).isTrue();
    assertThat(TypeUtils.isAssignableFrom(Serializable.class, Object.class)).isTrue();

    // Regular, non java wrapped classes.
    assertThat(TypeUtils.isTypeConvertible(AtomicInteger.class, Number.class)).isTrue();
    assertThat(TypeUtils.isAssignableFrom(AtomicInteger.class, Number.class)).isTrue();

    assertThat(TypeUtils.isTypeConvertible(NumericComparator.class, Comparator.class)).isTrue();
    assertThat(TypeUtils.isAssignableFrom(NumericComparator.class, Comparator.class)).isTrue();

    assertThat(TypeUtils.isTypeConvertible(PartitionedRegion.class, LocalRegion.class)).isTrue();
    assertThat(TypeUtils.isAssignableFrom(PartitionedRegion.class, LocalRegion.class)).isTrue();
  }
Can't test every possible combination so try the known, relevant ones.
geode-core/src/test/java/org/apache/geode/cache/query/internal/types/TypeUtilsJUnitTest.java