@Test
void toUpperCase() {

    assertThat(ASCII.toUpperCase(null)).isNull();
    assertThat(ASCII.toUpperCase("text")).isEqualTo("TEXT");
    assertThat(ASCII.toUpperCase("tExt")).isEqualTo("TEXT");
    assertThat(ASCII.toUpperCase("TEXT")).isEqualTo("TEXT");
    assertThat(ASCII.toUpperCase("01239_-")).isEqualTo("01239_-");
}