Add mutation Date.parse -> other parse methods

- Adds receiver specific selector mutations
- Closes #432

Changelog.md

@@ -1,3 +1,7 @@
+# Unreleased
+
+* Add mutation from `Date.parse` to more strict parsing methods #448
+
 # v0.8.5 2015-09-11
 
 * Fix misimplementation of block gluing operator that

config/flay.yml

@@ -1,3 +1,3 @@
 ---
 threshold: 18
-total_score: 1233
+total_score: 1239

lib/mutant.rb

@@ -50,6 +50,7 @@ require 'mutant/ast/named_children'
 require 'mutant/ast/node_predicates'
 require 'mutant/ast/meta'
 require 'mutant/ast/meta/send'
+require 'mutant/ast/meta/const'
 require 'mutant/ast/meta/symbol'
 require 'mutant/ast/meta/optarg'
 require 'mutant/ast/meta/resbody'

lib/mutant/ast/meta/const.rb

@@ -0,0 +1,24 @@
+module Mutant
+  module AST
+    # Node meta information mixin
+    module Meta
+
+      # Metadata for const nodes
+      class Const
+        include NamedChildren, Concord.new(:node), NodePredicates
+
+        children :base, :name
+
+        # Test if AST node is possibly a top level constant
+        #
+        # @return [Boolean]
+        #
+        # @api private
+        def possible_top_level?
+          base.nil? || n_cbase?(base)
+        end
+
+      end # Const
+    end # Meta
+  end # AST
+end # Mutant

lib/mutant/ast/meta/send.rb

@@ -5,7 +5,7 @@ module Mutant
 
       # Metadata for send nodes
       class Send
-        include NamedChildren, Concord.new(:node)
+        include NamedChildren, Concord.new(:node), NodePredicates
 
         children :receiver, :selector
 
@@ -56,6 +56,17 @@ module Mutant
           Types::BINARY_METHOD_OPERATORS.include?(selector)
         end
 
+        # Test if receiver is possibly a top level constant
+        #
+        # @return [Boolean]
+        #
+        # @api private
+        def receiver_possible_top_level_const?
+          return false unless receiver && n_const?(receiver)
+
+          Const.new(receiver).possible_top_level?
+        end
+
       end # Send
     end # Meta
   end # AST

lib/mutant/mutator/node/send.rb

@@ -3,6 +3,7 @@ module Mutant
     class Node
 
       # Namespace for send mutators
+      # rubocop:disable ClassLength
       class Send < self
         include AST::Types
 
@@ -34,6 +35,12 @@ module Mutant
           :< =>          %i[== <= eql? equal?]
         )
 
+        RECEIVER_SELECTOR_REPLACEMENTS = IceNine.deep_freeze(
+          Date: {
+            parse: %i[jd civil strptime iso8601 rfc3339 xmlschema rfc2822 rfc822 httpdate jisx0301]
+          }
+        )
+
       private
 
         # Perform dispatch
@@ -92,10 +99,25 @@ module Mutant
           emit_selector_replacement
           emit_const_get_mutation
           emit_argument_propagation
+          emit_receiver_selector_mutations
           mutate_receiver
           mutate_arguments
         end
 
+        # Emit selector mutations specific to top level constants
+        #
+        # @return [undefined]
+        #
+        # @api private
+        def emit_receiver_selector_mutations
+          return unless meta.receiver_possible_top_level_const?
+
+          RECEIVER_SELECTOR_REPLACEMENTS
+            .fetch(receiver.children.last, EMPTY_HASH)
+            .fetch(selector, EMPTY_ARRAY)
+            .each(&method(:emit_selector))
+        end
+
         # Emit mutation from `const_get` to const literal
         #
         # @return [undefined]

meta/date.rb

@@ -0,0 +1,57 @@
+Mutant::Meta::Example.add do
+  source 'Date.parse(nil)'
+
+  singleton_mutations
+  mutation 'Date.parse'
+  mutation 'self.parse(nil)'
+  mutation 'Date'
+  mutation 'Date.jd(nil)'
+  mutation 'Date.civil(nil)'
+  mutation 'Date.strptime(nil)'
+  mutation 'Date.iso8601(nil)'
+  mutation 'Date.rfc3339(nil)'
+  mutation 'Date.xmlschema(nil)'
+  mutation 'Date.rfc2822(nil)'
+  mutation 'Date.rfc822(nil)'
+  mutation 'Date.httpdate(nil)'
+  mutation 'Date.jisx0301(nil)'
+end
+
+Mutant::Meta::Example.add do
+  source '::Date.parse(nil)'
+
+  singleton_mutations
+  mutation '::Date.parse'
+  mutation 'Date.parse(nil)'
+  mutation 'self.parse(nil)'
+  mutation '::Date'
+  mutation '::Date.jd(nil)'
+  mutation '::Date.civil(nil)'
+  mutation '::Date.strptime(nil)'
+  mutation '::Date.iso8601(nil)'
+  mutation '::Date.rfc3339(nil)'
+  mutation '::Date.xmlschema(nil)'
+  mutation '::Date.rfc2822(nil)'
+  mutation '::Date.rfc822(nil)'
+  mutation '::Date.httpdate(nil)'
+  mutation '::Date.jisx0301(nil)'
+end
+
+Mutant::Meta::Example.add do
+  source 'Date.iso8601(nil)'
+
+  singleton_mutations
+  mutation 'Date.iso8601'
+  mutation 'self.iso8601(nil)'
+  mutation 'Date'
+end
+
+Mutant::Meta::Example.add do
+  source 'Foo::Date.parse(nil)'
+
+  singleton_mutations
+  mutation 'Foo::Date.parse'
+  mutation 'Foo::Date'
+  mutation 'Date.parse(nil)'
+  mutation 'self.parse(nil)'
+end

spec/unit/mutant/ast/meta/send/receiver_possible_top_level_const_predicate_spec.rb

@@ -0,0 +1,37 @@
+RSpec.describe Mutant::AST::Meta::Send, '#receiver_possible_top_level_const?' do
+  subject { described_class.new(node).receiver_possible_top_level_const? }
+
+  def parse(source)
+    Parser::CurrentRuby.parse(source)
+  end
+
+  context 'when implicit top level const' do
+    let(:node) { parse('Foo.bar') }
+
+    it { should be true }
+  end
+
+  context 'when cbase' do
+    let(:node) { parse('::Foo.bar') }
+
+    it { should be true }
+  end
+
+  context 'when nested const' do
+    let(:node) { parse('Baz::Foo.bar') }
+
+    it { should be false }
+  end
+
+  context 'when no receiver' do
+    let(:node) { parse('bar') }
+
+    it { should be false }
+  end
+
+  context 'when send receiver' do
+    let(:node) { parse('foo.bar') }
+
+    it { should be false }
+  end
+end