Are you speaking specifically automated type things like Wanikani or just in general? I can be more specific in my answer for what I use currently if I know that, but I will go ahead and tell you anyway.
I like Minna No Nihongo a lot, it is a textbook series like genki that has practice exercises at the end of each chapter and then tests after a few chapters etc. It has all the answers in the back so you can check whether you were correct or not. It also has extra writing practice books etc if you want more practice than what the book gives.
For an app or computer type thing I like both Hello Talk and italki. You can make up your own sentences/paragraphs etc and put them on there and native speakers will correct what you have written. I find it a great way to make up my own journal entries or whatever you want and post that to get feedback, good practice for creating sentences or whatever out of your own mind. You can also add speech or talk into hello talk to get feedback on pronunciation etc.
Other good resources I have used as far as questions are any of the jlpt like n5 or whatever level you are on books they have lots of question sections and usually have answer keys with them.
Maybe those suggestions will help a little =D