Random tests are currently completely broken: it only generates inputs like ((((((((( and expects 0 hours.

Also the author/reference solution is plain wrong: if it was correct the spec would actually be

Senior - works for 1 hour with no break.
Middle - works for 45-minute with a 15-minute break.
Junior - works for 1 hour with a 1 hour break.

Additionally, in case we receive an incorrect description of the garden, we need to handle the error:

It's unclear how we should handle the error; it's not mentioned, and the sample tests doesn't demonstrate this.

Could you explain how the math works on this example?

Junior - works for 1 hour with a 30-minute break.

howManyHours('(-{-(-', 'Junior') - result: '10 hour'

Two oaks and one birch take 5 hours to cut down. With a 30-minute break every hour, it takes 7.5 hours. Which rounds up to 8 hours. Why is the result 10 hours?