diff --git a/lib/mutant/runner/subject.rb b/lib/mutant/runner/subject.rb
index d6e40d37..1352f522 100644
--- a/lib/mutant/runner/subject.rb
+++ b/lib/mutant/runner/subject.rb
@@ -68,7 +68,7 @@ module Mutant
       # @api private
       #
       def run
-        @mutations = subject.map do |mutation|
+        @mutations = subject.mutations.map do |mutation|
           Mutation.run(config, mutation)
         end
       end
diff --git a/spec/unit/mutant/runner/config/success_predicate_spec.rb b/spec/unit/mutant/runner/config/success_predicate_spec.rb
index 674ecbd1..0b63ba45 100644
--- a/spec/unit/mutant/runner/config/success_predicate_spec.rb
+++ b/spec/unit/mutant/runner/config/success_predicate_spec.rb
@@ -12,8 +12,10 @@ describe Mutant::Runner::Config, '#success?' do
   let(:subject_b) { mock('Subject B', :fails? => false)                          }
 
   class DummySubjectRunner
-    def initialize(_config, subject)
-      @subject = subject
+    include Concord.new(:config, :subject)
+
+    def self.run(*args)
+      new(*args)
     end
 
     def failed?
diff --git a/spec/unit/mutant/runner/subject/mutations_spec.rb b/spec/unit/mutant/runner/subject/mutations_spec.rb
index 91b2c166..d46b857f 100644
--- a/spec/unit/mutant/runner/subject/mutations_spec.rb
+++ b/spec/unit/mutant/runner/subject/mutations_spec.rb
@@ -5,9 +5,9 @@ describe Mutant::Runner::Subject, '#mutations' do
 
   subject { object.mutations }
 
-  let(:config)           { mock('Config')   }
-  let(:mutation)         { mock('Mutation') }
-  let(:mutation_subject) { [mutation] }
+  let(:config)           { mock('Config')                            }
+  let(:mutation)         { mock('Mutation')                          }
+  let(:mutation_subject) { mock('Subject', :mutations => [mutation]) }
 
   class DummyRunner
     include Concord.new(:config, :mutation)
diff --git a/spec/unit/mutant/runner/subject/success_predicate_spec.rb b/spec/unit/mutant/runner/subject/success_predicate_spec.rb
new file mode 100644
index 00000000..05e14a4e
--- /dev/null
+++ b/spec/unit/mutant/runner/subject/success_predicate_spec.rb
@@ -0,0 +1,44 @@
+require 'spec_helper'
+
+describe Mutant::Runner::Subject, '#success?' do
+  subject { object.success? }
+
+  let(:object) { described_class.run(config, mutation_subject) }
+
+  let(:mutation_subject) { mock('Subject', :mutations => mutations) }
+  let(:config)           { mock('Config')                           }
+  let(:mutation_a)       { mock('Mutation A', :fails? => false)     }
+  let(:mutation_b)       { mock('Mutation B', :fails? => false)     }
+  let(:mutations)        { [mutation_a, mutation_b]                 }
+
+  class DummyMutationRunner
+    include Concord.new(:config, :mutation)
+
+    def self.run(*args)
+      new(*args)
+    end
+
+    def failed?
+      @mutation.fails?
+    end
+  end
+
+  before do
+    stub_const('Mutant::Runner::Mutation', DummyMutationRunner)
+  end
+
+  context 'without evil failed mutations' do
+    it { should be(true) }
+  end
+
+  context 'with failing noop mutation' do
+  end
+
+  context 'with failing evil mutations' do
+    before do
+      mutation_a.stub(:fails? => true)
+    end
+
+    it { should be(false) }
+  end
+end