Real porcelain Supertest Gasoline Porcelain Sign. Supertest Canada’s All Canadian Company. Supertest Petroleum came from the purchase of the Energy Oil Company in 1923. Supertest then operated as a oil and gas company in Canada 1923 to 1973. Its head office was in London, Ontario. It marketed itself as ‘Canada’s All-Canadian Company’, and was acquired by BP Canada in 1971.