Fix spec code style

spec/unit/mutant/matcher/compiler_spec.rb

@@ -24,7 +24,6 @@ describe Mutant::Matcher::Compiler do
 
     let(:matcher_config) { Mutant::Matcher::Config::DEFAULT }
 
-
     context 'on empty config' do
       let(:attributes) { {} }
 
@@ -54,13 +53,13 @@ describe Mutant::Matcher::Compiler do
 
         let(:expected_positive_matcher) { Mutant::Matcher::Chain.new([matcher_a]) }
 
-        let(:expected_predicate) {
+        let(:expected_predicate) do
           Morpher::Evaluator::Predicate::Negation.new(
             Morpher::Evaluator::Predicate::Boolean::Or.new([
               described_class::SubjectPrefix.new(expression_b)
             ])
           )
-        }
+        end
 
         it { should eql(expected_matcher) }
       end
@@ -75,11 +74,11 @@ describe Mutant::Matcher::Compiler do
 
         let(:expected_positive_matcher) { Mutant::Matcher::Chain.new([matcher_a]) }
 
-        let(:expected_predicate) {
+        let(:expected_predicate) do
           Morpher::Evaluator::Predicate::Boolean::Or.new([
             Morpher.compile(s(:eql, s(:attribute, :code), s(:static, 'foo')))
           ])
-        }
+        end
 
         it { should eql(expected_matcher) }
       end

spec/unit/mutant/matcher/filter_spec.rb

@@ -8,7 +8,7 @@ describe Mutant::Matcher::Filter do
     subject { object.each { |entry| yields << entry } }
 
     let(:matcher)   { [subject_a, subject_b] }
-    let(:predicate) { lambda { |subject| subject.eql?(subject_a) } }
+    let(:predicate) { ->(subject) { subject.eql?(subject_a) } }
 
     let(:subject_a) { double('Subject A') }
     let(:subject_b) { double('Subject B') }
@@ -24,7 +24,6 @@ describe Mutant::Matcher::Filter do
       end
     end
 
-
     it 'should yield subjects' do
       expect { subject }.to change { yields }.from([]).to([subject_a])
     end

spec/unit/mutant/matcher/method/instance_spec.rb

@@ -37,7 +37,9 @@ describe Mutant::Matcher::Method::Instance do
 
       it 'does warn' do
         subject
-        expect(reporter.warn_calls.last).to eql("#{method.inspect} does not have valid source location unable to emit matcher")
+        expect(reporter.warn_calls.last).to(
+          eql("#{method.inspect} does not have valid source location unable to emit matcher")
+        )
       end
     end
 

spec/unit/mutant/runner_spec.rb

@@ -1,5 +1,6 @@
 require 'spec_helper'
 
+# FIXME: This is not even close to a mutation covering spec.
 describe Mutant::Runner do
   let(:object) { described_class.new(env) }
 
@@ -14,7 +15,7 @@ describe Mutant::Runner do
       super
     end
 
-    def update(attributes)
+    def update(_attributes)
       self
     end
 
@@ -104,7 +105,9 @@ describe Mutant::Runner do
       its(:subject_results) { should eql(expected_subject_results) }
 
       before do
-        expect(Mutant::Isolation::None).to receive(:call).and_raise(Mutant::Isolation::Error.new('test-exception-message')).twice
+        expect(Mutant::Isolation::None).to receive(:call)
+          .twice
+          .and_raise(Mutant::Isolation::Error.new('test-exception-message'))
 
         expect(Mutant::Result::Test).to receive(:new).with(
           test:     test_a1,