@Test
public void testTrim() {

    final String nullString = null;
    final String emptyString = "";
    final String blankString = " ";
    final String string = " a ";
    assertThat(Strings.trim(nullString), is(nullValue()));
    assertThat(Strings.trim(emptyString), is(""));
    assertThat(Strings.trim(blankString), is(""));
    assertThat(Strings.trim(string), is("a"));
}