I believe this kata has an issue. For example, between '1999-03-20' and '1999-03-21' means you want only data for only one day. Starts-with-inclusive, ends-with-exclusive.
Description says nothing about exclusion of the last day of a trimester, but one may only complete this kata when he/she does so.

My solution works perfectly on my local machine with PostgreSQL, but this kata throws this at me:

expected collection contained:  [{:date1=>#<Date: 2023-01-21 ((2459966j,0s,0n),+0s,2299161j)>, :date2=>#<Date: 2023-03-31 ((2460035j,...,0s,0n),+0s,2299161j)>, :date2=>#<Date: 2023-03-31 ((2460035j,0s,0n),+0s,2299161j)>, :m=>1, :n=>50}]
actual collection contained:    [{:date1=>#<Date: 2023-01-21 ((2459966j,0s,0n),+0s,2299161j)>, :date2=>#<Date: 2023-03-31 ((2460035j,...0s,0n),+0s,2299161j)>, :date2=>#<Date: 2023-03-31 ((2460035j,0s,0n),+0s,2299161j)>, :m=>50, :n=>50}]

Does anybody know what do these n and m mean?

Same