Change to verified mutation generation

lib/mutant/cli/command/util.rb

@@ -78,7 +78,7 @@ def print_mutations(target)
               node:   target.node
             ).each do |mutation|
               Reporter::CLI::Printer::Mutation.call(
-                object: Mutant::Mutation::Evil.new(subject: target, node: mutation),
+                object: Mutant::Mutation::Evil.build(subject: target, node: mutation).from_right,
                 output: world.stdout
               )
             end

lib/mutant/meta/example.rb

@@ -61,7 +61,7 @@ def generated
           config: Mutation::Config::DEFAULT.with(operators:),
           node:
         ).map do |node|
-          Mutation::Evil.new(subject: self, node:)
+          Mutation::Evil.build(subject: self, node:).from_right
         end
       end
       memoize :generated

lib/mutant/meta/example/verification.rb

@@ -94,7 +94,7 @@ def unexpected
 
         def missing
           (example.expected.map(&:node) - mutations.map(&:node)).map do |node|
-            Mutation::Evil.new(subject: example, node:)
+            Mutation::Evil.build(subject: example, node:).from_right
           end
         end
         memoize :missing

lib/mutant/mutation.rb

@@ -4,7 +4,7 @@ module Mutant
   # Represent a mutated node with its subject
   class Mutation
     include AbstractType, Adamantium
-    include Anima.new(:subject, :node)
+    include Anima.new(:subject, :node, :source)
 
     CODE_DELIMITER = "\0"
     CODE_RANGE     = (..4)
@@ -17,14 +17,6 @@ def code
     end
     memoize :code
 
-    # Normalized mutation source
-    #
-    # @return [String]
-    def source
-      Unparser.unparse(node)
-    end
-    memoize :source
-
     # Identification string
     #
     # @return [String]
@@ -84,6 +76,11 @@ def diff
     end
     memoize :diff
 
+    def self.build(node:, subject:)
+      Unparser.unparse_either(node)
+        .fmap { |source| new(node:, subject:, source:) }
+    end
+
   private
 
     def sha1

lib/mutant/subject.rb

@@ -16,7 +16,7 @@ def mutations
           config: config.mutation,
           node:
         ).map do |mutant|
-          Mutation::Evil.new(subject: self, node: wrap_node(mutant))
+          Mutation::Evil.build(subject: self, node: wrap_node(mutant)).from_right
         end
       )
     end
@@ -92,7 +92,7 @@ def source
   private
 
     def neutral_mutation
-      Mutation::Neutral.new(subject: self, node: wrap_node(node))
+      Mutation::Neutral.build(subject: self, node: wrap_node(node)).from_right
     end
 
     def wrap_node(node)

spec/support/shared_context.rb

@@ -38,11 +38,11 @@ def setup_shared_context
     let(:subjects)        { [subject_a]                                              }
 
     let(:mutation_a) do
-      Mutant::Mutation::Evil.new(subject: subject_a, node: mutation_a_node)
+      Mutant::Mutation::Evil.build(subject: subject_a, node: mutation_a_node).from_right
     end
 
     let(:mutation_b) do
-      Mutant::Mutation::Evil.new(subject: subject_a, node: mutation_b_node)
+      Mutant::Mutation::Evil.build(subject: subject_a, node: mutation_b_node).from_right
     end
 
     let(:job_a) do

spec/unit/mutant/meta/example/verification_spec.rb

@@ -26,7 +26,7 @@
 
   let(:mutations) do
     generated_nodes.map do |node|
-      Mutant::Mutation::Evil.new(subject: example, node:)
+      Mutant::Mutation::Evil.build(subject: example, node:).from_right
     end
   end
 

spec/unit/mutant/meta/example_spec.rb

@@ -26,7 +26,7 @@
 
   let(:mutations) do
     mutation_nodes.map do |node|
-      Mutant::Mutation::Evil.new(subject: object, node:)
+      Mutant::Mutation::Evil.build(subject: object, node:).from_right
     end
   end
 

spec/unit/mutant/mutation_spec.rb

@@ -14,7 +14,7 @@
   let(:root_node) { s(:int, 1)                       }
 
   let(:object) do
-    mutation_class.new(subject: mutation_subject, node:)
+    mutation_class.build(subject: mutation_subject, node:).from_right
   end
 
   let(:mutation_subject) do

spec/unit/mutant/reporter/cli/printer/mutation_result_spec.rb

@@ -84,7 +84,7 @@
         with(:mutation_a_test_result) { { passed: false } }
 
         let(:mutation_a) do
-          Mutant::Mutation::Neutral.new(subject: subject_a, node: s(:true))
+          Mutant::Mutation::Neutral.build(subject: subject_a, node: s(:true)).from_right
         end
 
         it_reports(<<~REPORT)
@@ -106,7 +106,7 @@
         with(:mutation_a_test_result) { { passed: false } }
 
         let(:mutation_a) do
-          Mutant::Mutation::Noop.new(subject: subject_a, node: s(:true))
+          Mutant::Mutation::Noop.build(subject: subject_a, node: s(:true)).from_right
         end
 
         it_reports(<<~REPORT)

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

@@ -155,18 +155,18 @@ def foo; end
 
     let(:expected) do
       [
-        Mutant::Mutation::Neutral.new(
+        Mutant::Mutation::Neutral.build(
           subject: object,
           node:    s(:begin, s(:def, :foo, s(:args), nil), memoize_node)
-        ),
-        Mutant::Mutation::Evil.new(
+        ).from_right,
+        Mutant::Mutation::Evil.build(
           subject: object,
           node:    s(:begin, s(:def, :foo, s(:args), s(:send, nil, :raise)), memoize_node)
-        ),
-        Mutant::Mutation::Evil.new(
+        ).from_right,
+        Mutant::Mutation::Evil.build(
           subject: object,
           node:    s(:begin, s(:def, :foo, s(:args), s(:zsuper)), memoize_node)
-        )
+        ).from_right
       ]
     end
 

spec/unit/mutant/subject_spec.rb

@@ -100,9 +100,9 @@ def foo
 
     it 'generates neutral and evil mutations' do
       should eql([
-        Mutant::Mutation::Neutral.new(subject: object, node:),
-        Mutant::Mutation::Evil.new(subject: object, node: mutation_a),
-        Mutant::Mutation::Evil.new(subject: object, node: mutation_b)
+        Mutant::Mutation::Neutral.build(subject: object, node:).from_right,
+        Mutant::Mutation::Evil.build(subject: object, node: mutation_a).from_right,
+        Mutant::Mutation::Evil.build(subject: object, node: mutation_b).from_right
       ])
     end
   end