Refactor cassandra tests

[anusudarsan]

Release notes

(x) This is not user-visible or is docs only, and no release notes are required.

[ebyhr]

optional) We could add a helper class implementing TemporaryRelation:

    public static class TestKeyspace
            implements TemporaryRelation
    {
        private final CassandraSession session;
        private final String name;

        public TestKeyspace(CassandraSession session, String namePrefix)
        {
            this.session = requireNonNull(session, "session is null");
            this.name = namePrefix + "_" + randomNameSuffix();
            session.execute("CREATE KEYSPACE IF NOT EXISTS " + name + " WITH REPLICATION = {'class':'SimpleStrategy', 'replication_factor': 1}");
        }

        @Override
        public String getName()
        {
            return name;
        }

        @Override
        public void close()
        {
            session.execute("DROP KEYSPACE IF EXISTS " + name);
        }
    }

[anusudarsan]

optional) We could add a helper class implementing TemporaryRelation:

the create and drop does not seem to be executed on the "name". for e.g testUpperCaseNameUnescapedInCassandra uses upper case to create and lowercase to drop. Looks like these actions are case sensitive. So I guess I will skip this suggestion