In rspec-core 2.7.0, Rspec::Core::RakeTask does not execute any specs when the rcov attribute is true; minimal test case.
This seems to be due to the spec/autorun change mentioned in the 2.7.0 changelog (the rcov mode of the task assumes that spec scripts can be executed directly). A workaround is to require 'spec/autorun' in your spec helper or individual specs.
Verified still failing with RSpec 1.12.0.
Also, this looks like a dupe of #422.
There's also talk of dropping RCov support in #625.
Thank you @Peeja. Closing this one in favor of keeping discussion in #422.