// sanity checks
        assertNotSame(a1, a2);
        assertNotSame(lr1, lr2);
        assertNotSame(rr1, rr2);

        DefaultMavenMetadataCache.CacheKey k1 =
                new DefaultMavenMetadataCache.CacheKey(a1, false, lr1, Collections.singletonList(rr1));
        DefaultMavenMetadataCache.CacheKey k2 =
                new DefaultMavenMetadataCache.CacheKey(a2, false, lr2, Collections.singletonList(rr2));