### Question:
SphereInternalUtils { @SuppressWarnings("varargs") public static <T> List<T> listOf(final T element, final T[] array) { final List<T> result = new ArrayList<>(1 + array.length); result.add(element); result.addAll(asList(array)); return result; } private  SphereInternalUtils(); static String join(final List<T> list); static List<T> immutableCopyOf(final List<T> list); @SafeVarargs @SuppressWarnings("varargs") static List<T> asImmutableList(final T ... elements); @SuppressWarnings("varargs") static List<T> listOf(final T element, final T[] array); static List<T> listOf(final List<T> elements, final T element); static List<T> listOf(List<? extends T> first, List<? extends T> second); static List<T> reverse(final List<T> list); @SafeVarargs @SuppressWarnings("varargs") static Set<T> asSet(final T ... params); static Set<T> setOf(final T element, final Set<T> set); static Set<T> setOf(final Set<T> first, final Set<T> second); static Set<T> setOf(final T element, final T[] array); static String slugifyUnique(final String s); static String slugify(final String s); static V getOrThrow(final Map<K, V> map, final K key, Supplier<E> exceptionSupplier); static Map<K, V> immutableCopyOf(final Map<K, V> map); static Map<K, V> copyOf(final Map<K, V> map); static Map<K, V> mapOf(final K key, final V value); static Map<K, V> mapOf(final K key1, final V value1, final K key2, final V value2); static boolean isEmpty(final Iterable<?> iterable); static Iterable<T> requireNonEmpty(final Iterable<T> iterable); static List<T> toList(final Iterable<T> iterable); static Stream<T> toStream(final Iterable<T> iterable);  }### Answer:
@Test public void testListOfOneListAndElement() throws Exception { final List<Integer> integers = Arrays.asList(1, 2, 3); final List<Integer> combined = SphereInternalUtils.listOf(integers, 4); assertThat(combined).isEqualTo(Arrays.asList(1, 2, 3, 4)); }
@Test public void testListOfTwoLists() throws Exception { final List<Integer> firstList = Arrays.asList(1, 2, 3); final List<Integer> secondList = Arrays.asList(4, 5, 6); final List<Integer> combined = SphereInternalUtils.listOf(firstList, secondList); assertThat(combined).isEqualTo(Arrays.asList(1, 2, 3, 4, 5, 6)); }