public final void isNaN() {
    isEqualTo(NaN);
  }
@Test
  public void isNaN() {
    assertThat(Float.NaN).isNaN();
    assertThatIsNaNFails(1.23f);
    assertThatIsNaNFails(Float.POSITIVE_INFINITY);
    assertThatIsNaNFails(Float.NEGATIVE_INFINITY);
    assertThatIsNaNFails(null);
  }