I can share my experience! For some background, I am currently studying in the US and applied for citizenship in Oct. 2018 while in the US.
I received an email from CIC on Feb 16 asking me to appear for the test on March 02, 2018. However, I had already made plans to travel abroad during that period (Mar 02 - Mar 11). On the same day, I sent an email to CIC with my case ID, requesting for a new date by stating that I was currently a student in the US and would be traveling abroad. I also gave them dates that would not work for me (some dates during the month of April due to school exams).
On Feb 19, IRCC responded that they would reschedule the test after March 12, 2018.
On Mar 14, CIC gave me a new test date of April 09. I took the test on that date, received my scores, etc. Finally, on April 24, I was invited to the oath ceremony, which will be held on May 08.