assertThat(Strings.nullToEmpty("a")).isEqualTo("a");
  }

  public void testEmptyToNull() {
    assertThat(Strings.emptyToNull(null)).isNull();
    assertThat(Strings.emptyToNull("")).isNull();
    assertThat(Strings.emptyToNull("a")).isEqualTo("a");
  }

  public void testIsNullOrEmpty() {
    assertTrue(Strings.isNullOrEmpty(null));
    assertTrue(Strings.isNullOrEmpty(""));

    assertThat(Strings.nullToEmpty("a")).isEqualTo("a");
  }

  public void testEmptyToNull() {
    assertThat(Strings.emptyToNull(null)).isNull();
    assertThat(Strings.emptyToNull("")).isNull();
    assertThat(Strings.emptyToNull("a")).isEqualTo("a");
  }

  public void testIsNullOrEmpty() {
    assertTrue(Strings.isNullOrEmpty(null));
    assertTrue(Strings.isNullOrEmpty(""));

      appendUserObject(builder, ((DelegatingToFuture) localValue).future);
      builder.append("]");
    } else {
      String pendingDescription;
      try {
        pendingDescription = Strings.emptyToNull(pendingToString());
      } catch (Throwable e) {
        /*
         * We want to catch (Exception | StackOverflowError), but we can't under environments where
         * StackOverflowError doesn't exist.
         */