In #549, we added unittests for dispatch AtCoder and Codeforces.
To increasing test coverage, we should add unittests for other contest (HackerRank, CS Academy, ...).

Not only tests for all other contests, tests for the part of contests are welcome.

We should add more data to the judgehosts overview page:

• which judging is currently judged by each judgehost
• summary line with load averages

CP Editor supports GUI in multiple languages, including English, Chinese, and Russian. However, the developers don't know every language, and the translators don't always have time, so we need help translating the text.

The reasoning for this is the same as for problem testers; problem testers can be used as a model for this feature.

https://www.youtube.com/channel/UCD8yeTczadqdARzQUp29PJw

His videos are pretty nice (though there isn't C++ code); probably worth adding to modules as needed

We sometimes want to run tests which are not associated to specific problems (e.g. generating inputs using srand() and rand(), and check the output with assert()). For this, we can use Hello World as a dummy problem.
However, this technique is not trivial, so we should print hint messages when test files with no PROBLEM