YA SciFi. Teen astronauts are sent to another planet. They first undergo trials/ tests to select the best candidates (e.g., have to get tangled fairy lights working; drop in elevator). Read around 2017-2018. Spoiler ahead.

[Kris]

seren, I added some details to the header/topic title. You can update it by clicking the small "edit" link after the header. This only works on the full Desktop website - not the Mobile website or app. (On the Mobile website, click the "Desktop version" link at the bottom of the page.)

[Kate]

Maybe The Raging Ones? they go to another planet, and they have to undergo trials but I don't remember exactly what they had to do.

[Becca]

What Goes Up by Katie Kennedy - if you search inside for 'Christmas lights' on Google Books you can find the bit with tangled fairy lights.

https://www.google.co.uk/books/editio...

[Sarah]

Becca, I'm not the OP but just wanted to thank you for this one! I thought from the OP's description this sounded like an interesting book and I hoped someone would find it, so I was really pleased when you identified it. I bought it on Kindle and just finished reading it, and it's a brilliant read! So, I hope the OP reads this and also gets to reread the book (I'm sure it's the one they were talking about), but, even if the OP doesn't come back, you've helped one person find a great book!

[Becca]

Sarah wrote: "Becca, I'm not the OP but just wanted to thank you for this one! I thought from the OP's description this sounded like an interesting book and I hoped someone would find it, so I was really pleased..."

Ahh, that's lovely to hear! Glad you enjoyed it.

[Kris]

seren, What Goes Up by Katie Kennedy - Becca's suggestion - sounds like your book.

Google preview - https://books.google.com/books?id=niT...

Quotes:
Is that clear?” It was clear. “Go!” she shouted. Eddie pulled the box lid up with both hands and stared inside. It was a strand of Christmas lights, very long, incredibly tangled. All the sockets were empty; the bottom was filled with loose bulbs ...

His wires were lying in an orderly coil, but only half the bulbs were in. He'd wind up with a negative score. The whistle blew. “Leave them,” Ms. Bauer said, standing up from her desk. “Follow me.” They trailed her out of the hangar and across a ...

[Kris]

OP (original poster) account is deleted. Moving to the "Now we'll never know" folder.