The HMRC Corporation Tax online service supports 'test in live' service for commercial software users. 'Test in live' lets users submit a sample Company Tax Return as a test to HM Revenue and Customs (HMRC) before sending for real. Please check with your supplier whether or not the product you're using supports 'test in live'.
Please note: There is no testing service for customers using the HMRC Corporation Tax online filing software. The accounts and computations templates make sure your return meets the format requirements