@Test
public void testTrimToEmpty() {

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