Throughout all of the lessons I have done so far, .not_to has always been used (as far as I have noticed) but in 10_drink_answer.rb on the 'is not full' test, .to_not is used.
On the Introduction to RSpec lesson at the end of the Basic syntax subsection, this is even said:
"The expect method is also chained with .to for positive expectations, or .to_not/.not_to for negative expectations. We prefer .not_to."
Throughout all of the lessons I have done so far, .not_to has always been used (as far as I have noticed) but in 10_drink_answer.rb on the 'is not full' test, .to_not is used.
On the Introduction to RSpec lesson at the end of the Basic syntax subsection, this is even said:
"The expect method is also chained with .to for positive expectations, or .to_not/.not_to for negative expectations. We prefer .not_to."