I'd expect them to be published at ioinformatics.org, but it looks like there are only problem statements there. misof, do you know anything about official solutions and tests of IOI 2017?

Test data status of major OI in 2017 :

• BOI 2017 : Test data △ (Online judge given) | Solution file or editorial X
• APIO 2017 : Test data X | Solution file or editorial X
• CEOI 2017 : Test data O | Solution file or editorial O
• IOI 2017 : Test data △ (Online judge given) | Solution file or editorial X

Comparing from last year (and most year before that):

• BOI 2016 : Test data O | Solution file or editorial O
• APIO 2016 : Test data O | Solution file or editorial O
• CEOI 2016 : Test data O | Solution file or editorial O
• IOI 2016 : Test data O | Solution file or editorial O

One might skip the solution part — although it's much nicer to open them — but I think the test data should be public, especially if you think your contest is big. OI problems are not only for contest purposes but also for training. Providing OJs are not bad, but they greatly limit the ability to check the test data or use it in other environment (especially for tutors)

Also, huge applause to APIO 2017 organizers! Not only delaying contest results for a month, now they don't care anything about their post-contest works. Breaking decade long tradition of test data disclosure is an awesome accomplishment :D

Auto comment: topic has been updated by farmersrice (previous revision, new revision, compare).

Finally solutions are here, and also one additional online judge to solve most of the problems :)