Refactoring towards Diff, step 7

Author: beatmadsen

lib/files_in_my_diff/commit.rb

@@ -12,11 +12,11 @@ def initialize(folder:, revision:, file_strategy: TmpDir::FileStrategy, git_stra
 
       def call
         validate_folder!
-        validate_revision!
-        sha = @git_strategy.object.sha
-        @git_strategy.diff
-        dir = @file_strategy.create_tmp_dir(sha)
-        { dir:, sha: }
+        diff = @git_strategy.diff(@revision)
+        diff.validate!
+        diff.changes
+        dir = @file_strategy.create_tmp_dir(diff.sha)
+        { dir:, sha: diff.sha }
       end
 
       private

lib/files_in_my_diff/git.rb

@@ -26,37 +26,24 @@ def changes
     end
 
     class Adapter
-      def object(revision = nil)
-        @object ||= if revision.is_a?(::Git::Object::AbstractObject)
-                      @repo.object(revision.sha)
-                    else
-                      @repo.object(revision)
-                    end
-      rescue ::Git::FailedError
-        nil
-      end
-
       def initialize(folder:, repo: ::Git.open(folder))
         @repo = repo
       end
 
-      def revision_exists?(revision)
-        @object = object(revision)
-        @object && true
-      rescue ::Git::FailedError
-        false
-      end
-
-      def diff2(revision)
+      def diff(revision)
         Diff.new(object: object(revision), revision:)
       end
 
-      def diff
-        @object.diff_parent.map do |change|
-          { path: change.path, type: change.type }
+      private
+
+      def object(revision)
+        if revision.is_a?(::Git::Object::AbstractObject)
+          @repo.object(revision.sha)
+        else
+          @repo.object(revision)
         end
-      rescue ::Git::FailedError => e
-        raise DiffError, "Failed to get diff for #{@object.sha}: #{e.message}"
+      rescue ::Git::FailedError
+        nil
       end
     end
   end

test/commit/main_test.rb

@@ -23,18 +23,6 @@ def test_that_main_validates_that_revision_exists
         end
       end
 
-      def test_that_main_accepts_a_git_object_as_a_revision
-        refute_nil subject(revision: GitObjectStub.new).call
-      end
-
-      def test_that_main_accepts_an_integer_version_as_a_revision
-        refute_nil subject(revision: 32).call
-      end
-
-      def test_that_main_accepts_a_relative_revision
-        refute_nil subject(revision: 'HEAD~1').call
-      end
-
       def test_that_error_on_tmp_dir_resolution_is_propagated
         file_strategy = file_strategy_stub(create_success: false)
         assert_raises(TmpDir::DirectoryError) do
@@ -59,17 +47,8 @@ def file_strategy_stub(dir_exists: true, create_success: true)
         FileStrategyStub.new(dir_exists, create_success)
       end
 
-      def git_strategy_stub(revision_exists: true, object: GitObjectStub.new, diff_success: true)
-        GitStrategyStub.new(revision_exists, object, diff_success)
-      end
-
-      class GitObjectStub < ::Git::Object::AbstractObject
-        attr_reader :sha
-
-        def initialize(sha: 'abc')
-          super(nil, nil)
-          @sha = sha
-        end
+      def git_strategy_stub(revision_exists: true, diff_success: true)
+        GitStrategyStub.new(revision_exists, diff_success)
       end
 
       class FileStrategyStub
@@ -90,22 +69,30 @@ def create_tmp_dir(_sha)
       end
 
       class GitStrategyStub
-        attr_reader :object
-
-        def initialize(revision_exists, object, diff_success)
+        def initialize(revision_exists, diff_success)
           @revision_exists = revision_exists
-          @object = object
           @diff_success = diff_success
         end
 
-        def revision_exists?(_revision)
-          @revision_exists
+        def diff(_revision)
+          return InvalidDiffStub unless @revision_exists
+          raise Git::DiffError unless @diff_success
+
+          ValidDiffStub
         end
+      end
 
-        def diff
-          raise Git::DiffError unless @diff_success
+      module InvalidDiffStub
+        def self.validate!
+          raise ValidationError
+        end
+      end
 
-          { 'file_1' => :changed, 'file_2' => :deleted, 'file_3' => :added }
+      module ValidDiffStub
+        class << self
+          def validate! = true
+          def sha = 'abcd1234'
+          def changes = []
         end
       end
     end

test/git/adapter_test.rb

@@ -6,21 +6,21 @@ module FilesInMyDiff
   module Git
     class AdapterTest < Minitest::Test
       def test_it_returns_a_diff_instance
-        assert_instance_of Diff, subject.diff2('x')
+        assert_instance_of Diff, subject.diff('x')
       end
 
       def test_that_diff_is_evaluated_by_sha_for_git_objects
         mock = GitRepoMock.new
         sha = 'y'
-        subject(repo: mock).diff2(GitObjectStub.new(sha:))
+        subject(repo: mock).diff(GitObjectStub.new(sha:))
 
         assert_equal mock.object_called_with, sha
       end
 
       def test_that_diff_is_evaluated_by_revision_for_strings
         mock = GitRepoMock.new
         revision = 'HEAD~1'
-        subject(repo: mock).diff2(revision)
+        subject(repo: mock).diff(revision)
 
         assert_equal mock.object_called_with, revision
       end