* @param val The string to be interpolated.
     * @param callback The function to resolve variable values.
     * @return The interpolated string, or null if the input was null.
     */
    @Nullable
    default String interpolate(@Nullable String val, @Nullable UnaryOperator<String> callback) {
        return interpolate(val, callback, false);
    }

    /**
     * Interpolates a single string value using the provided callback function.

    SortedSet<String> set = of("e", "a", "f", "b", "d", "c");
    SortedSet<String> subset = set.subSet("c", "e");
    SortedSet<String> copy = copyOf(subset);
    assertEquals(subset, copy);
  }

  public void testCopyOf_headSet() {
    SortedSet<String> set = of("e", "a", "f", "b", "d", "c");
    SortedSet<String> headset = set.headSet("d");
    SortedSet<String> copy = copyOf(headset);
    assertEquals(headset, copy);
  }

    public void setFrom(String from, String personal) {
        doSetFrom(from, personal);
    }

    public void addTo(String to) {
        doAddTo(to);
    }

    public void addTo(String to, String personal) {
        doAddTo(to, personal);
    }

    public void addCc(String cc) {
        doAddCc(cc);
    }

    public void addCc(String cc, String personal) {
        doAddCc(cc, personal);

    public void setId_Equal(String id) {
        setId_Term(id, null);
    }

    public void setId_Equal(String id, ConditionOptionCall<TermQueryBuilder> opLambda) {
        setId_Term(id, opLambda);
    }

    public void setId_Term(String id) {
        setId_Term(id, null);
    }

    public void setId_Term(String id, ConditionOptionCall<TermQueryBuilder> opLambda) {

        ArrayMap<String, String> m = new ArrayMap<String, String>(1);
        m.getEntryAt(1);
    }

    /**
     * @throws Exception
     */
    @Test
    public void testSerialize() throws Exception {
        @SuppressWarnings("unchecked")
        ArrayMap<String, String> copy = (ArrayMap<String, String>) SerializeUtil.serialize(map);

        String query4 = "test query";
        String escaped4 = SuggestUtil.escapeWildcardQuery(query4);
        assertEquals("test query", escaped4);

        // Test with multiple wildcards
        String query5 = "***???";
        String escaped5 = SuggestUtil.escapeWildcardQuery(query5);
        assertEquals("\\*\\*\\*\\?\\?\\?", escaped5);

        // Test empty string
        String query6 = "";

    @Override
    String normalizeWord(String word) {
      return firstCharOnlyToUpper(word);
    }

    @Override
    String normalizeFirstWord(String word) {
      return Ascii.toLowerCase(word);
    }
  },

  /** Java and C++ class naming convention, e.g., "UpperCamel". */
  UPPER_CAMEL(CharMatcher.inRange('A', 'Z'), "") {
    @Override
    String normalizeWord(String word) {

        assertNotNull(emptyUnicodeStringTrue.buffer, "Buffer should not be null for empty string with zterm");
        assertEquals(1, emptyUnicodeStringTrue.buffer.length, "Buffer length should be 1 for empty string with zterm");
        assertEquals(0, emptyUnicodeStringTrue.buffer[0], "Buffer should contain only zero for empty string with zterm");

        // Test with an empty string and zterm = false

  public void copyOfImmutableNetwork_optimized() {
    Network<String, String> network1 =
        ImmutableNetwork.copyOf(NetworkBuilder.directed().<String, String>build());
    Network<String, String> network2 = ImmutableNetwork.copyOf(network1);

    assertThat(network2).isSameInstanceAs(network1);
  }

  @Test
  public void edgesConnecting_directed() {
    MutableNetwork<String, String> mutableNetwork =

  public static class ImmutableSortedMapGenerator extends TestStringSortedMapGenerator {
    @Override
    public SortedMap<String, String> create(Entry<String, String>[] entries) {
      ImmutableSortedMap.Builder<String, String> builder = ImmutableSortedMap.naturalOrder();
      for (Entry<String, String> entry : entries) {
        checkNotNull(entry);
        builder.put(entry.getKey(), entry.getValue());
      }