*     FIRST_LETTER_MULTIMAP.put('a', "pple");
   *     FIRST_LETTER_MULTIMAP.put('a', "sparagus");
   *     FIRST_LETTER_MULTIMAP.put('c', "arrot");
   *     FIRST_LETTER_MULTIMAP.put('c', "herry");
   * }
   * }
   *
   * <p>To collect to an {@link ImmutableMultimap}, use either {@link
   * ImmutableSetMultimap#toImmutableSetMultimap} or {@link
   * ImmutableListMultimap#toImmutableListMultimap}.
   *

    }

    @Test
    public void test_getWords() throws Exception {
        List<String> words = new ArrayList<>();
        words.add("apple");
        words.add("banana");
        words.add("cherry");

        PopularWordsResponse response = new PopularWordsResponse("test-index", 100, words, 10, new ArrayList<>());

        assertNotNull(response.getWords());
        assertEquals(3, response.getWords().size());

    }

    @Test
    @DisplayName("Should join with multi-character delimiter")
    void testJoinWithMultiCharDelimiter() {
        String result = StringUtil.join(" - ", "apple", "banana", "cherry");
        assertEquals("apple - banana - cherry", result);
    }

    @Test
    @DisplayName("Should handle null delimiter by inserting 'null' string")
    void testJoinWithNullDelimiter() {

 * needed, use {@code supplier::get}.
 *
 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/FunctionalExplained">the use of {@code Function}</a>.
 *
 * @author Harry Heymann
 * @since 2.0
 */
@GwtCompatible
@FunctionalInterface
public interface Supplier<T extends @Nullable Object> extends java.util.function.Supplier<T> {
  /**

 * those classes explore numerous corner cases. The intent here is to confirm that everything is
 * wired up properly.
 *
 * @author Craig Berry
 */
@NullUnmarked
public final class HostSpecifierTest extends TestCase {

  private static final ImmutableList<String> GOOD_IPS =
      ImmutableList.of("1.2.3.4", "2001:db8::1", "[2001:db8::1]");

 * them as a {@link String}. Example:
 *
 * {@snippet :
 * Joiner joiner = Joiner.on("; ").skipNulls();
 *  . . .
 * return joiner.join("Harry", null, "Ron", "Hermione");
 * }
 *
 * <p>This returns the string {@code "Harry; Ron; Hermione"}. Note that all input elements are
 * converted to strings using {@link Object#toString()} before being appended.
 *

 * java.util.function.Supplier}, making conversion code necessary only in one direction. At that
 * time, this interface will be officially discouraged.
 *
 * @author Harry Heymann
 * @since 2.0
 */
@GwtCompatible
public interface Supplier<T extends @Nullable Object> {
  /**
   * Retrieves an instance of the appropriate type. The returned object may or may not be a new

import junit.framework.TestCase;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Tests com.google.common.base.Suppliers.
 *
 * @author Laurence Gonsalves
 * @author Harry Heymann
 */
@NullMarked
@GwtCompatible
public class SuppliersTest extends TestCase {

  static class CountingSupplier implements Supplier<Integer> {
    int calls = 0;

    @Override

import junit.framework.TestCase;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Tests com.google.common.base.Suppliers.
 *
 * @author Laurence Gonsalves
 * @author Harry Heymann
 */
@NullMarked
@GwtCompatible
public class SuppliersTest extends TestCase {

  static class CountingSupplier implements Supplier<Integer> {
    int calls = 0;

    @Override

import org.jspecify.annotations.Nullable;

/**
 * Useful suppliers.
 *
 * <p>All methods return serializable suppliers as long as they're given serializable parameters.
 *
 * @author Laurence Gonsalves
 * @author Harry Heymann
 * @since 2.0
 */
@GwtCompatible
public final class Suppliers {
  private Suppliers() {}

  /**
   * Returns a new supplier which is the composition of the provided function and supplier. In other