rake error

--> Idempotence test in progress (can take a few minutes)...
--> Starting Ansible Run...
Idempotence test passed.
--> Executing ansible-lint...
--> Executing rubocop on *.rb files found in spec/...
Inspecting 2 files
..

2 files inspected, no offenses detected
--> Executing serverspec tests found in spec/...
rake aborted!
LoadError: cannot load such file -- rspec/core/rake_task
/Users/tennis/PycharmProjects/delivery-gdc-secrets/ansible/roles/consul/.molecule/rakefile:4:in `<top (required)>'
/usr/local/lib/ruby/gems/2.4.0/gems/rake-12.0.0/exe/rake:27:in `<top (required)>'
(See full trace by running task with --trace)
ERROR: 

  RAN: /usr/local/bin/rake --rakefile=.molecule/rakefile

  STDOUT:


  STDERR: