@Test
public void testLowercaseFirstLetter() {

    assertThat(Strings.lowercaseFirstLetter(""), is(""));
    assertThat(Strings.lowercaseFirstLetter("A"), is("a"));
    assertThat(Strings.lowercaseFirstLetter("AA"), is("aA"));
    assertThat(Strings.lowercaseFirstLetter("a"), is("a"));
    assertThat(Strings.lowercaseFirstLetter("aB"), is("aB"));
}