Merge pull request #933 from mbj/add/mutant-diff-ranges

Add Mutant::Diff::Ranges

Author: mbj

lib/mutant.rb

@@ -180,6 +180,8 @@ module Mutant
 require 'mutant/reporter/cli/printer/test_result'
 require 'mutant/reporter/cli/format'
 require 'mutant/repository'
+require 'mutant/repository/diff'
+require 'mutant/repository/diff/ranges'
 require 'mutant/variable'
 require 'mutant/zombifier'
 require 'mutant/range'

lib/mutant/repository.rb

@@ -19,67 +19,5 @@ def call(subject)
       end
 
     end # SubjectFilter
-
-    # Diff between two objects in repository
-    class Diff
-      include Adamantium, Anima.new(:world, :from, :to)
-
-      HEAD = 'HEAD'
-
-      # Test if diff changes file at line range
-      #
-      # @param [Pathname] path
-      # @param [Range<Integer>] line_range
-      #
-      # @return [Boolean]
-      #
-      # @raise [RepositoryError]
-      #   when git command failed
-      def touches?(path, line_range)
-        return false unless within_working_directory?(path) && tracks?(path)
-
-        command = %W[
-          git log
-          #{from}...#{to}
-          --ignore-all-space
-          -L #{line_range.begin},#{line_range.end}:#{path}
-        ]
-
-        stdout, status = world.open3.capture2(*command, binmode: true)
-
-        fail RepositoryError, "Command #{command} failed!" unless status.success?
-
-        !stdout.empty?
-      end
-
-    private
-
-      # Test if path is tracked in repository
-      #
-      # FIXME: Cache results, to avoid spending time on producing redundant results.
-      #
-      # @param [Pathname] path
-      #
-      # @return [Boolean]
-      def tracks?(path)
-        command = %W[git ls-files --error-unmatch -- #{path}]
-        world.kernel.system(
-          *command,
-          out: File::NULL,
-          err: File::NULL
-        )
-      end
-
-      # Test if the path is within the current working directory
-      #
-      # @param [Pathname] path
-      #
-      # @return [TrueClass, nil]
-      def within_working_directory?(path)
-        working_directory = world.pathname.pwd
-        path.ascend { |parent| return true if working_directory.eql?(parent) }
-      end
-
-    end # Diff
   end # Repository
 end # Mutant

lib/mutant/repository/diff.rb

@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+module Mutant
+  module Repository
+    # Diff between two objects in repository
+    class Diff
+      include Adamantium, Anima.new(:world, :from, :to)
+
+      HEAD = 'HEAD'
+
+      # Test if diff changes file at line range
+      #
+      # @param [Pathname] path
+      # @param [Range<Integer>] line_range
+      #
+      # @return [Boolean]
+      #
+      # @raise [RepositoryError]
+      #   when git command failed
+      def touches?(path, line_range)
+        return false unless within_working_directory?(path) && tracks?(path)
+
+        command = %W[
+          git log
+          #{from}...#{to}
+          --ignore-all-space
+          -L #{line_range.begin},#{line_range.end}:#{path}
+        ]
+
+        stdout, status = world.open3.capture2(*command, binmode: true)
+
+        fail RepositoryError, "Command #{command} failed!" unless status.success?
+
+        !stdout.empty?
+      end
+
+    private
+
+      # Test if path is tracked in repository
+      #
+      # FIXME: Cache results, to avoid spending time on producing redundant results.
+      #
+      # @param [Pathname] path
+      #
+      # @return [Boolean]
+      def tracks?(path)
+        command = %W[git ls-files --error-unmatch -- #{path}]
+        world.kernel.system(
+          *command,
+          out: File::NULL,
+          err: File::NULL
+        )
+      end
+
+      # Test if the path is within the current working directory
+      #
+      # @param [Pathname] path
+      #
+      # @return [TrueClass, nil]
+      def within_working_directory?(path)
+        working_directory = world.pathname.pwd
+        path.ascend { |parent| return true if working_directory.eql?(parent) }
+      end
+
+    end # Diff
+  end # Repository
+end # Mutant

lib/mutant/repository/diff/ranges.rb

@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+module Mutant
+  module Repository
+    class Diff
+      module Ranges
+        DECIMAL = /(?:0|[1-9]\d*)/.freeze
+        REGEXP  = /\A@@ -(#{DECIMAL})(?:,(#{DECIMAL}))? \+(#{DECIMAL})(?:,(#{DECIMAL}))? @@/.freeze
+
+        private_constant(*constants(false))
+
+        # Parse a unified diff into ranges
+        #
+        # @param [String]
+        #
+        # @return [Set<Range<Integer>>]
+        def self.parse(diff)
+          diff.lines.flat_map(&method(:parse_ranges)).to_set
+        end
+
+        # Parse ranges from line
+        #
+        # @param [String] line
+        #
+        # @return [Array<Range<Integer>>]
+        def self.parse_ranges(line)
+          match = REGEXP.match(line) or return EMPTY_ARRAY
+
+          match
+            .captures
+            .each_slice(2)
+            .map { |start, offset| mk_range(start, offset) }
+            .reject { |range| range.end < range.begin }
+        end
+        private_class_method :parse_ranges
+
+        # Construct a range from start point and offset
+        #
+        # @param [String] start
+        # @param [String, nil] offset
+        #
+        # @return [Range<Integer>]
+        def self.mk_range(start, offset)
+          start = Integer(start)
+
+          ::Range.new(start, start + (offset ? Integer(offset).pred : 0))
+        end
+        private_class_method :mk_range
+      end # Ranges
+    end # Diff
+  end # Repository
+end # Ranges

spec/unit/mutant/repository/diff/ranges_spec.rb

@@ -0,0 +1,180 @@
+# frozen_string_literal: true
+
+describe Mutant::Repository::Diff::Ranges do
+  describe '.parse' do
+    def apply
+      described_class.parse(diff)
+    end
+
+    let(:diff) do
+      Tempfile.open('old') do |old_file|
+        old_file.write(old)
+        old_file.flush
+        Tempfile.open('new') do |new_file|
+          new_file.write(new)
+          new_file.flush
+          # rubocop:disable Lint/UnneededSplatExpansion
+          stdout, status = Open3.capture2(
+            *%W[
+              git
+              diff
+              --no-index
+              --unified=0
+              --
+              #{old_file.path}
+              #{new_file.path}
+            ]
+          )
+          # rubocop:enable Lint/UnneededSplatExpansion
+
+          fail unless [0, 256].include?(status.to_i)
+
+          stdout
+        end
+      end
+    end
+
+    context 'on empty diff' do
+      let(:old) { '' }
+      let(:new) { '' }
+
+      it 'returns emtpy set' do
+        expect(apply).to eql(Set.new)
+      end
+    end
+
+    context 'on empty old' do
+      let(:old) { '' }
+
+      context 'adding a single line' do
+        let(:new) do
+          <<~'STR'
+            a
+          STR
+        end
+
+        it 'returns expected set' do
+          expect(apply).to eql([1..1].to_set)
+        end
+      end
+
+      context 'adding a multiple lines' do
+        let(:old) { '' }
+
+        let(:new) do
+          <<~'STR'
+            a
+            b
+          STR
+        end
+
+        it 'returns expected set' do
+          expect(apply).to eql([1..2].to_set)
+        end
+      end
+    end
+
+    context 'on empty new' do
+      let(:new) { '' }
+
+      context 'removing a single line' do
+        let(:old) do
+          <<~'STR'
+            a
+          STR
+        end
+
+        it 'returns expected set' do
+          expect(apply).to eql([1..1].to_set)
+        end
+      end
+
+      context 'removing a multiple lines' do
+        let(:old) do
+          <<~'STR'
+            a
+            b
+          STR
+        end
+
+        it 'returns expected set' do
+          expect(apply).to eql([1..2].to_set)
+        end
+      end
+    end
+
+    context 'single line modification' do
+      let(:old) do
+        <<~'STR'
+          a
+          b
+          c
+          a
+        STR
+      end
+
+      let(:new) do
+        <<~'STR'
+          a
+          b
+          b
+          a
+        STR
+      end
+
+      it 'returns expected set' do
+        expect(apply).to eql([3..3].to_set)
+      end
+    end
+
+    context 'nonempty old and new' do
+      context 'single line addition' do
+        let(:old) do
+          <<~'STR'
+            a
+            b
+            a
+          STR
+        end
+
+        let(:new) do
+          <<~'STR'
+            a
+            b
+            b
+            a
+          STR
+        end
+
+        it 'returns expected set' do
+          expect(apply).to eql([3..3].to_set)
+        end
+      end
+      context 'multi line modification' do
+        let(:old) do
+          <<~'STR'
+            a
+            b
+            c
+            d
+            a
+          STR
+        end
+
+        let(:new) do
+          <<~'STR'
+            a
+            b
+            b
+            b
+            a
+          STR
+        end
+
+        it 'returns expected set' do
+          expect(apply).to eql([3..4].to_set)
+        end
+      end
+    end
+  end
+end