mutant output

$ CI=true be mutant -j1 -I . -r mutant-freezer --use rspec 'Foo*'Mutant configuration:
Matcher:         #<Mutant::Matcher::Config match_expressions: [Foo*]>
Integration:     Mutant::Integration::Rspec
Expect Coverage: 100.00%
Jobs:            1
Includes:        ["."]
Requires:        ["mutant-freezer"]
(00/08) 100% - killtime: 0.00s runtime: 0.00s overhead: 0.00s
(07/08)  87% - killtime: 0.18s runtime: 1.01s overhead: 0.83s
Foo#bar:/Users/johnbackus/Dropbox/coding/gists/mutant-freezer.rb:13
- rspec:0:./mutant-freezer.rb:22/Foo#bar should not freeze
neutral:Foo#bar:/Users/johnbackus/Dropbox/coding/gists/mutant-freezer.rb:13:7e6ca
--- Neutral failure ---
Original code was inserted unmutated. And the test did NOT PASS.
Your tests do not pass initially or you found a bug in mutant / unparser.
Subject AST:
(def :bar
  (args)
  (send
    (const nil :DontFreeze) :new))
Unparsed Source:
def bar
  DontFreeze.new
end
memoize(:bar)
Test Result:
- 1 @ runtime: 0.010801
  - rspec:0:./mutant-freezer.rb:22/Foo#bar should not freeze
Test Output:
F

Failures:

  1) Foo#bar should not freeze
     Failure/Error: fail "I said don't freeze me!"
     RuntimeError:
       I said don't freeze me!
     # ./mutant-freezer.rb:6:in `freeze'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/ice_nine-0.11.1/lib/ice_nine/freezer/object.rb:19:in `guarded_deep_freeze'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/ice_nine-0.11.1/lib/ice_nine/freezer.rb:100:in `block in guarded_deep_freeze'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/ice_nine-0.11.1/lib/ice_nine/support/recursion_guard.rb:51:in `guard'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/ice_nine-0.11.1/lib/ice_nine/freezer.rb:99:in `guarded_deep_freeze'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/ice_nine-0.11.1/lib/ice_nine/freezer.rb:54:in `deep_freeze!'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/ice_nine-0.11.1/lib/ice_nine.rb:59:in `deep_freeze!'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/adamantium-0.2.0/lib/adamantium/freezer.rb:83:in `freeze'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/adamantium-0.2.0/lib/adamantium/freezer.rb:50:in `freeze_value'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/adamantium-0.2.0/lib/adamantium/freezer.rb:34:in `call'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/memoizable-0.4.2/lib/memoizable/method_builder.rb:117:in `block (3 levels) in create_memoized_method'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/memoizable-0.4.2/lib/memoizable/memory.rb:63:in `block (3 levels) in fetch'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/thread_safe-0.3.5/lib/thread_safe/cache.rb:58:in `fetch'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/memoizable-0.4.2/lib/memoizable/memory.rb:62:in `block (2 levels) in fetch'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/memoizable-0.4.2/lib/memoizable/memory.rb:61:in `block in fetch'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/thread_safe-0.3.5/lib/thread_safe/cache.rb:58:in `fetch'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/memoizable-0.4.2/lib/memoizable/memory.rb:60:in `fetch'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/memoizable-0.4.2/lib/memoizable/method_builder.rb:116:in `block (2 levels) in create_memoized_method'
     # ./mutant-freezer.rb:23:in `block (2 levels) in <top (required)>'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-rspec-0.8.2/lib/mutant/integration/rspec.rb:68:in `call'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/env.rb:64:in `block in run_mutation_tests'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/isolation.rb:48:in `call'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/isolation.rb:48:in `block (3 levels) in call'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/isolation.rb:45:in `open'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/isolation.rb:45:in `block (2 levels) in call'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/isolation.rb:44:in `fork'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/isolation.rb:44:in `block in call'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/isolation.rb:41:in `pipe'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/isolation.rb:41:in `call'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/env.rb:62:in `run_mutation_tests'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/env.rb:39:in `kill'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/parallel/worker.rb:64:in `call'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/parallel/worker.rb:64:in `handle_job'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/parallel/worker.rb:47:in `handle'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/parallel/worker.rb:31:in `run'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/parallel/worker.rb:15:in `run'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/parallel/master.rb:49:in `block (2 levels) in run'
     # /Users/johnbackus/.rvm/gems/ruby-2.2.3/gems/mutant-0.8.5/lib/mutant/actor/env.rb:16:in `block in spawn'

Finished in 0.00219 seconds (files took 0.28024 seconds to load)
1 example, 1 failure

Failed examples:

rspec  # Foo#bar should not freeze
-----------------------
Mutant configuration:
Matcher:         #<Mutant::Matcher::Config match_expressions: [Foo*]>
Integration:     Mutant::Integration::Rspec
Expect Coverage: 100.00%
Jobs:            1
Includes:        ["."]
Requires:        ["mutant-freezer"]
Subjects:        1
Mutations:       8
Kills:           7
Alive:           1
Runtime:         1.01s
Killtime:        0.18s
Overhead:        455.89%
Coverage:        87.50%
Expected:        100.00%

mutant-freezer.rb

require 'adamantium'
require 'rspec'

class DontFreeze
  def freeze
    fail "I said don't freeze me!"
  end
end

class Foo
  include Adamantium

  def bar
    DontFreeze.new
  end
  memoize :bar, freezer: :noop
end

RSpec.describe Foo, '#bar' do
  let(:foo) { described_class.new }

  it 'should not freeze' do
    expect(foo.bar).to be_an_instance_of(DontFreeze)
  end
end

rspec output

$ rspec mutant-freezer.rb
.

Finished in 0.00082 seconds (files took 0.21123 seconds to load)
1 example, 0 failures