The Devonshire South Central by-election will be a test for all three of the Island's political parties.It is good for democracy that Premier Paula Cox scheduled it for November 1, just before Parliament is due to reconvene. If Craig Cannonier wins the by-election, it means that the One Bermuda Alliance will have an Opposition Leader in the House of Assembly.Ms Cox could have played politics on this as it was well within her powers to delay the vote. That would have caused embarrassment and difficulties for the OBA. It is likely that such a move would have backfired for Ms Cox as she would have been condemned for it, but it is welcome that she did the right thing all the same. Naturally, the biggest test for the OBA is to hold the seat that interim party leader John Barritt vacated once Mr Cannonier won the OBA's leadership vote, as he had promised to do.It is not surprising that the governing Progressive Labour Party and the United Bermuda Party under Kim Swan have criticised this “handover” as arrogance, as opposed to a sacrifice on Mr Barritt's part, but this should not get much traction. If a leader of the OBA was going to be elected by the OBA, someone was going to have to move aside to make room for the new leader, who constitutionally must be an MP to be Opposition Leader.Mr Cannonier should say that he hopes the by-election will not be a walkover, but will be a tough campaign with a healthy and vigorous debate and he should commit to see every single constituent.The big question is whether the United Bermuda Party assuming it can run under that banner will mount a campaign. In the 2007 general election, Mr Barritt, running as a UBP candidate, won 85 percent of the vote, so a UBP candidate would have a better chance in this election of winning the seat than the PLP.Mr Cannonier will want to secure as close a proportion of the vote as Mr Barritt did. That will not be easy, since Mr Barritt was a diligent constituency MP, but that must be the OBA's goal. He will also want to try to convert as many PLP supporters in the constituency as possible in order to demonstrate that the OBA has a genuine chance of winning a general election. That's not easy to interpret in any constituency and it is even harder when only 15 percent of the electorate voted PLP in the last election, but that's the test.If the UBP does put in a candidate, and it must if it wishes to be taken seriously, it needs to win a substantial proportion of the vote to show it is viable. If that happens, that will show that the potential for split votes in Opposition seats are likely in a general election, which will hearten PLP strategists and those supporters of the UBP who did not join the OBA.If the UBP fails to carry a material number of voters, let alone a majority, then it will be time for Kim Swan and Charlie Swan to fold up their tents and either join the OBA or come to some kind of accommodation with them. In a general election, the real risk for both Opposition parties is that if the OBA runs candidates in their constituencies, it will split the vote and hand both seats over to the PLP. So curiously, it is in the PLP's best interests for a UBP candidate to make a good showing.For the PLP, the main test is simply to hold the 15 percent of the vote Linda Merritt won last time, or better still, to take advantage of the split vote and increase the PLP's share. If that were to happen, then Ms Cox would almost certainly call a Christmas general election. If the PLP saw its share of the vote drop precipitously, that would not necessarily rule out a Christmas poll, because a by-election in an Opposition stronghold, especially if turnout is lower than in a general election, would be a poor barometer. But it might give Ms Cox pause.Leaving tactics aside, this newspaper hopes that the campaign will be vigorous and that the many issues facing the Island will get a full airing.