@Test
public void firstNotBlank() {

    assertNull(Strings.firstNotBlank());
    assertNull(Strings.firstNotBlank(EMPTY));
    assertNull(Strings.firstNotBlank((String)null));
    assertNull(Strings.firstNotBlank(" "));
    assertNull(Strings.firstNotBlank("\t"));
    assertNull(Strings.firstNotBlank("\n"));
    assertNull(Strings.firstNotBlank(EMPTY, "\n", "\t", "\n", null, " "));
    assertEquals(X, Strings.firstNotBlank(X));
    assertEquals(X, Strings.firstNotBlank(X, Y));
    assertEquals(X, Strings.firstNotBlank(X, EMPTY));
    assertEquals(X, Strings.firstNotBlank(X, " "));
    assertEquals(X, Strings.firstNotBlank(X));
}