Merge branch 'transactions' of https://github.com/AlfonsoUceda/model …

…into AlfonsoUceda-transactions

lib/lotus/model/adapters/abstract.rb

@@ -162,6 +162,18 @@ def command(query)
         def query(collection, &blk)
           raise NotImplementedError
         end
+
+        # Create a transaction
+        # Only supported by SqlAdapter
+        #
+        # @param options [Hash] options for transaction
+        #
+        # @see Lotus::Model::Adapters::SqlAdapter#transaction
+        #
+        # @since x.x.x
+        def transaction(options = {})
+          yield
+        end
       end
     end
   end

lib/lotus/model/adapters/sql_adapter.rb

@@ -132,6 +132,20 @@ def query(collection, context = nil, &blk)
           Sql::Query.new(_collection(collection), context, &blk)
         end
 
+        # Create a transaction
+        #
+        # @param options [Hash] options for transaction
+        #
+        # @see http://sequel.jeremyevans.net/rdoc/files/doc/transactions_rdoc.html
+        #
+        # @api private
+        # @since x.x.x
+        def transaction(options = {})
+          @connection.transaction(options) do
+            yield
+          end
+        end
+
         private
 
         # Returns a collection from the given name.

lib/lotus/repository.rb

@@ -505,6 +505,75 @@ def clear
         @adapter.clear(collection)
       end
 
+      # Create a transaction
+      #
+      # @param options [Hash] options for transaction
+      #
+      # @see Lotus::Model::Adapters::SqlAdapter#transaction
+      #
+      # @since x.x.x
+      #
+      # @example
+      #   require 'lotus/model'
+      #
+      #   class Article
+      #     include Lotus::Entity
+      #     attributes :title, :body
+      #   end
+      #
+      #   class ArticleRepository
+      #     include Lotus::Repository
+      #   end
+      #
+      #   article = Article.new title: 'Introducing transactions', body: 'lorem ipsum'
+      #
+      #   ArticleRepository.transaction do
+      #     ArticleRepository.create(article)
+      #   end
+      #
+      # @example
+      #   require 'lotus/model'
+      #
+      #   class Article
+      #     include Lotus::Entity
+      #     attributes :title, :body
+      #   end
+      #
+      #   class ArticleRepository
+      #     include Lotus::Repository
+      #   end
+      #
+      #   article = Article.new title: 'Introducing transactions', body: 'lorem ipsum'
+      #
+      #   ArticleRepository.transaction(rollback: :always) do
+      #     ArticleRepository.create(article)
+      #   end # ROLLBACK
+      #   # no exception raised
+      #
+      # @example
+      #   require 'lotus/model'
+      #
+      #   class Article
+      #     include Lotus::Entity
+      #     attributes :title, :body
+      #   end
+      #
+      #   class ArticleRepository
+      #     include Lotus::Repository
+      #   end
+      #
+      #   article = Article.new title: 'Introducing transactions', body: 'lorem ipsum'
+      #
+      #   ArticleRepository.transaction(rollback: :reraise) do
+      #     raise Exception
+      #   end # ROLLBACK
+      #   # Exception raised
+      def transaction(options = {})
+        @adapter.transaction(options) do
+          yield
+        end
+      end
+
       private
       # Fabricates a query and yields the given block to access the low level
       # APIs exposed by the query itself.

test/repository_test.rb

@@ -316,4 +316,77 @@ def to_int
       end
     end
   end
+
+  describe "with sql adapter" do
+    before do
+      UserRepository.adapter    = Lotus::Model::Adapters::SqlAdapter.new(MAPPER, SQLITE_CONNECTION_STRING)
+      ArticleRepository.adapter = Lotus::Model::Adapters::SqlAdapter.new(MAPPER, SQLITE_CONNECTION_STRING)
+
+      UserRepository.collection    = :users
+      ArticleRepository.collection = :articles
+
+      UserRepository.clear
+      ArticleRepository.clear
+
+      ArticleRepository.create(article1)
+    end
+
+    describe '.transaction' do
+      it 'if an exception is raised the size of articles is equal to 1' do
+        ArticleRepository.all.size.must_equal 1
+        exception = -> { ArticleRepository.transaction do
+          ArticleRepository.create(article2)
+          raise Exception
+        end }
+        exception.must_raise Exception
+        ArticleRepository.all.size.must_equal 1
+      end
+
+      it "if an exception isn't raised the size of articles is equal to 2" do
+        ArticleRepository.all.size.must_equal 1
+        ArticleRepository.transaction do
+          ArticleRepository.create(article2)
+        end
+        ArticleRepository.all.size.must_equal 2
+      end
+
+      describe 'using options' do
+        it 'rollback: :always option' do
+          ArticleRepository.all.size.must_equal 1
+          ArticleRepository.transaction(rollback: :always) do
+            ArticleRepository.create(article2)
+          end
+          ArticleRepository.all.size.must_equal 1
+        end
+
+        it 'rollback: :reraise option' do
+          ArticleRepository.all.size.must_equal 1
+          -> { ArticleRepository.transaction(rollback: :reraise) do
+            raise Exception
+          end }.must_raise Exception
+        end
+      end
+    end
+  end
+
+  describe "with memory adapter" do
+    before do
+      UserRepository.adapter    = Lotus::Model::Adapters::MemoryAdapter.new(MAPPER, nil)
+      ArticleRepository.adapter = Lotus::Model::Adapters::MemoryAdapter.new(MAPPER, nil)
+
+      UserRepository.collection    = :users
+      ArticleRepository.collection = :articles
+
+      UserRepository.clear
+      ArticleRepository.clear
+    end
+
+    describe '.transaction' do
+      it "an exception is raised because of memory adapter doesn't support transactions" do
+        -> { ArticleRepository.transaction do
+          raise "boom"
+        end }.must_raise RuntimeError
+      end
+    end
+  end
 end