In Canadian English, it’s common to say “write a test” when you are the one being examined. As in, you’re writing your answers on the paper.
Here’s a brief conversation on the topic:
other examples:
https://www.cs.cmu.edu/~steffan/canadianisms.html
Wanikani doesn’t accept this answer, and I’ve gotten this answer wrong 3 or 4 times already for this reason. Can this be an acceptable answer for all the poor Canadians out there?
Tagging @Safarigirl さん and @MrInnerPeace さん 
Would you say “write a test” if there’s no written part?
I think 受験 is most commonly used in the context of school finals/entrance exams, but in theory it’s taking any exam, which doesn’t have to be written.
The JP-JP dictionary defines the word as 「試験を受けること」. 試験 is defined as an examination of an ability, nothing about it being written.
One can also say “sit a test”. Not sure if that’s accepted. Why not just add a synonym?
Yes, at least in Canada you’d say “write a test”, even if it were a multiple choice test.
Let me rephrase that, any test you sit down and do on paper would be “writing a test”. It wouldn’t for a sports test.
No I mean, when you don’t have to deal with text at all, like a driving test?
Edit: yes, that’s what I thought.
I think you can add a synonym for yourself, since for the most part it’s a correct meaning. Not sure if the writing limitation matters much for it to be an official entry.
In Australia, “write a test” means to actually create the thing in the first place - i.e. come up with the questions and such.
If WaniKani tries to add every regional variation as an answer, they’ll be here all day. Your best bet is to add a user synonym, which becomes an answer that WaniKani will also accept as correct (unless it’s something that’s explicitly been blocked due to being too dissimilar).
Every example Wanikani provides suggests this is a test you sit down and write. There’s nothing about a non-written example, so my assumption was this was only for written tests.
Weblio defines 受験 as 試験を受けること, and subsequently 試験 as 入学・入社・登用などの採否を決めるため、問題に答えさせたり実技をさせたりして、学力・知識・能力などを判断・評価すること (emphasis mine), so the word does in theory cover practical examinations.
…and in practice it also covers theoretical examinations…
Hiberno-English does this too, so I’m guessing there’s other BE related variants that use this too.
I’m generally for adding regional variations, but I don’t think they should for things like this where the variation means something related but very clearly wrong in other versions.
Canadian here. At least in the multiple places I lived, always said and always heard others say “take a test”. Except in the context of medical examination, in which case it was get or have a test/got or had a test.
Medical examinations don’t come under the meaning of 受験, though. 
It’s the same in American English. I’ve never heard someone use “write a test” to mean taking a test. I’d assume it’s referring to preparing an exam as an instructor. I think this is a case where using a user synonym is the best option.