HeaderName { public static HeaderName of(String value) { return new HeaderName(value); } private  HeaderName(String value); static HeaderName of(String value); @Override boolean equals(Object obj); @Override int hashCode(); @Override String toString();  }
@Test public void testEquivalence() { equivalenceTester() .addEquivalentGroup(HeaderName.of("foo"), HeaderName.of("FOO"), HeaderName.of("foo")) .addEquivalentGroup(HeaderName.of("bar"), HeaderName.of("BAR"), HeaderName.of("bar")) .check(); }