@Test
  public void getRegionEntryTypeShouldReturnTheProperTypeImplementation() {
    ObjectTypeAssert.assertThat(TypeUtils.getRegionEntryType(mock(Region.class)))
        .resolves(Region.Entry.class).isObject();
    ObjectTypeAssert.assertThat(TypeUtils.getRegionEntryType(mock(BucketRegion.class)))
        .resolves(Region.Entry.class).isObject();
    ObjectTypeAssert.assertThat(TypeUtils.getRegionEntryType(mock(AbstractRegion.class)))
        .resolves(Region.Entry.class).isObject();
    ObjectTypeAssert.assertThat(TypeUtils.getRegionEntryType(mock(PartitionedRegion.class)))
        .resolves(Region.Entry.class).isObject();
  }
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