Mastery by Testing Out is too easy compared to regular route
At any point in a lesson you can try to "test out." Testing out is essentially just an untimed lesson, and it jumps you straight to Master level.
After I have learned a lesson, I can either do a bunch of translations and possibly several bonus rounds, or I can just do the equivalent of one untimed (therefore easier) bonus round. Both allow me to "master" the level, but the second option is clearly much easier. Even leaving aside all the translations, the bonus rounds alone are harder than just testing out.
Usually I opt to do the translations and stuff, because I'm only doing this for myself after all and I want to learn. However, in my most recent lesson I was having difficulties in the bonus round, so said "whatever" and just tested out. Obviously this makes no sense.
I propose that testing out should only make you have "Learned" the lesson, and not "Mastered" it. This would serve the same purpose (allowing users to jump ahead if they know the content), but still require that the user do some translations and bonus rounds in order to have truly "mastered" it.
I see your point but I disagree.
Whenever I start a new topic, I do not know the contents yet, but by the time I finished all the lessons, I usually do and I want to round off the topic properly. I like being able to do so with a test so that I can consider it done and move on.
Mastering a topic by doing translations and practicing costs just wáy too much time and it annoys and therefor demotivates me, specially because the translation-documents and the practice-sentences are not exactly closely related to the topic. If this were the case, fair enough. But it isn't. :( I also often find that the document I have to translate for in order to advance in my topic has already been almost completed! Therefor, all the relatively easy sentences (the ones I feel up to trying) are gone. Trying at the hardest and longest ones will not prove very effective, so testing out of a topic is the only reasonable option left and I'm very glad it's there.