The best replacement for stub is mock.

The best alternatives to stub are rated as following:
★★★★★  mock
★★★  driver
★★  italic
★★  italic nib
★★  stub
★★  proxy
★  shim
★  paystub
★  cursive italic
★  skeleton java
★  expect
★  pay stub
★  skeleton
★  stubb
  w2
  expect rhino mocks
  eigrp

Your alternative for stub is not listed? Suggest!
Speaking about stub, one probably shouldn't forget about rspec.

Other search terms related to stub and their ratings are:
★★★★★ rspec
You have in mind a companion for stub and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of stub in all years. Click on graph for more.
stub
mock
driver