Implement Recipe::DSL#evaluate method:

Move recipe DSL evaluation in a dedicated #evaluate method, instead of
evaluating the code during the DSL instantiation.

lib/producer/core/recipe.rb

@@ -13,7 +13,7 @@ module Producer
       end
 
       def evaluate
-        dsl = DSL.new(@code)
+        dsl = DSL.new(@code).evaluate
         dsl.tasks.each.map(&:evaluate)
       end
 
@@ -22,12 +22,18 @@ module Producer
         attr_reader :tasks
 
         def initialize(code = nil, &block)
+          @code   = code
+          @block  = block
           @tasks  = []
-          if code
-            instance_eval code
-          else
-            instance_eval &block
         end
+
+        def evaluate
+          if @code
+            instance_eval @code
+          else
+            instance_eval &@block
+          end
+          self
         end
 
 

spec/producer/core/recipe_spec.rb

@@ -41,22 +41,47 @@ module Producer::Core
 
 
     describe Recipe::DSL do
+      let(:code)    { Proc.new { } }
       subject(:dsl) { Recipe::DSL.new &code }
 
       describe '#initialize' do
-        let(:code) { Proc.new { raise 'error from recipe' } }
+        context 'when a string of code is given as argument' do
+          subject(:dsl) { Recipe::DSL.new 'nil' }
 
+          it 'returns the DSL instance' do
+            expect(dsl).to be_a Recipe::DSL
+          end
+        end
+
+        context 'when a code block is given as argument' do
+          subject(:dsl) { Recipe::DSL.new Proc.new { } }
+
+          it 'returns the DSL instance' do
+            expect(dsl).to be_a Recipe::DSL
+          end
+        end
+      end
+
+      describe '#evaluate' do
         it 'evaluates its code' do
-          expect { dsl }.to raise_error(RuntimeError, 'error from recipe')
+          dsl = Recipe::DSL.new { raise 'error from recipe' }
+          expect { dsl.evaluate }.to raise_error(RuntimeError, 'error from recipe')
+        end
+
+        it 'returns itself' do
+          expect(dsl.evaluate).to eq dsl
         end
       end
 
+      context 'DSL specific methods' do
+        subject(:dsl) { Recipe::DSL.new(&code).evaluate }
+
         describe '#source' do
           let(:code)    { "source '#{fixture_path_for 'recipes/error'}'" }
           subject(:dsl) { Recipe::DSL.new code }
 
           it 'sources the recipe given as argument' do
-          expect { dsl }.to raise_error(RuntimeError, 'error from recipe')
+            expect { dsl.evaluate }.to raise_error(RuntimeError, 'error from recipe')
           end
         end
 
@@ -79,3 +104,4 @@ module Producer::Core
       end
     end
   end
+end