### Question:
ImmutableCharacterEncoding implements CharacterEncoding { @Override public String toHeader() { return name().toLowerCase(Locale.ENGLISH); } ImmutableCharacterEncoding(Charset charset); @Override boolean isWildcard(); @Override String name(); @Override Charset charset(); @Override String toHeader(); @Override int hashCode(); @Override boolean equals(Object obj); @Override String toString();  }### Answer:
@Test public void wildcardCharacterEncodingHeaderRepresentationIsValid() throws Exception { ImmutableCharacterEncoding sut = wildcard(); assertThat(sut.toHeader(),equalTo("*")); }
@Test public void regularCharacterEncodingHeaderRepresentationIsValid() throws Exception { ImmutableCharacterEncoding sut = regular(); assertThat(sut.toHeader(),equalTo("utf-8")); }