Success is defined as Improvement
To test progress and reveal strengths and weak spots you need to take a test swim periodically. Depending on the course or group you are in, you may have a test swim assigned at the beginning or end of each stage.
Remember that the results are just information which will show you how well new skills have been integrated into your swimming system. Data that reveals weak spots is good news because it reveals what needs more work and shows you where you need to concentrate your effort in your precious practice times.
Success is defined as improvement, not perfection.
More specifically, success is indicated by an improvement in your external results because of specific changes you’ve made in your internal control. Improvements in quality (it feels better, easier) come before improvements in quantity (it makes me move farther, faster), so don’t overlook those internal improvements when seeing your external results in the test swims.
For a simple rating system, see Simple Rating System for Your Practice Results.