Extract Task#template code in Template class

features/task_template.feature

@@ -1,17 +1,11 @@
 Feature: `template' task keyword
 
-  Background:
-    Given a file named "basic.erb" with:
+  Scenario: renders an ERB template file
+    Given a file named "templates/basic.erb" with:
       """
       basic template
       """
-    Given a file named "variables.erb" with:
-      """
-      <%= @foo %>
-      """
-
-  Scenario: renders an ERB template file
-    Given a recipe with:
+    And a recipe with:
       """
       task(:echo_template) { echo template 'basic' }
       """
@@ -19,9 +13,25 @@ Feature: `template' task keyword
     Then the output must contain "basic template"
 
   Scenario: renders ERB with given attributes as member data
-    Given a recipe with:
+    Given a file named "templates/variables.erb" with:
+      """
+      <%= @foo %>
+      """
+    And a recipe with:
       """
       task(:echo_template) { echo template('variables', foo: 'bar') }
       """
     When I execute the recipe
     Then the output must contain "bar"
+
+  Scenario: renders without `templates' search path
+    Given a file named "templates/basic.erb" with:
+      """
+      basic template
+      """
+    And a recipe with:
+      """
+      task(:echo_template) { echo template './templates/basic' }
+      """
+    When I execute the recipe
+    Then the output must contain "basic template"

lib/producer/core.rb

@@ -41,5 +41,6 @@ require 'producer/core/remote'
 require 'producer/core/remote/environment'
 require 'producer/core/remote/fs'
 require 'producer/core/task'
+require 'producer/core/template'
 require 'producer/core/version'
 require 'producer/core/worker'

lib/producer/core/task.rb

@@ -59,22 +59,7 @@ module Producer
       end
 
       def template(path, variables = {})
-        path = "#{path}.erb"
-        tpl = ERB.new(File.read(path), nil, '-')
-        tpl.filename = path
-        tpl.result build_erb_binding variables
-      end
-
-
-      private
-
-      def build_erb_binding(variables)
-        Object.new.instance_eval do |o|
-          variables.each do |k, v|
-            o.instance_variable_set "@#{k}", v
-          end
-          binding
-        end
+        Template.new(path).render variables
       end
     end
   end

lib/producer/core/template.rb

@@ -0,0 +1,34 @@
+module Producer
+  module Core
+    class Template
+      SEARCH_PATH = 'templates'.freeze
+
+      def initialize(path, search_path: SEARCH_PATH)
+        @path         = Pathname.new("#{path}.erb")
+        @search_path  = Pathname.new(search_path)
+      end
+
+      def render(variables = {})
+        tpl = ERB.new(File.read(resolve_path), nil, '-')
+        tpl.filename = resolve_path.to_s
+        tpl.result build_erb_binding variables
+      end
+
+
+      private
+
+      def resolve_path
+        if @path.to_s =~ /\A\.\// then @path else @search_path + @path end
+      end
+
+      def build_erb_binding(variables)
+        Object.new.instance_eval do |o|
+          variables.each do |k, v|
+            o.instance_variable_set "@#{k}", v
+          end
+          binding
+        end
+      end
+    end
+  end
+end

spec/fixtures/templates/basic.erb

@@ -0,0 +1 @@
+basic template

spec/fixtures/templates/variables.erb

@@ -0,0 +1 @@
+<%= @foo %>

spec/producer/core/template_spec.rb

@@ -0,0 +1,33 @@
+require 'spec_helper'
+
+module Producer::Core
+  describe Template do
+    include FixturesHelpers
+
+    let(:path)          { 'basic' }
+    let(:search_path)   { fixture_path_for 'templates' }
+    subject(:template)  { described_class.new path, search_path: search_path }
+
+    describe '#render' do
+      it 'renders ERB templates' do
+        expect(template.render).to eq "basic template\n"
+      end
+
+      context 'when variables are given' do
+        let(:path) { 'variables' }
+
+        it 'declares given variables in ERB render binding' do
+          expect(template.render foo: 'bar').to eq "bar\n"
+        end
+      end
+
+      context 'when relative path is requested' do
+        let(:path) { fixture_path_for('templates/basic').insert 0, './' }
+
+        it 'does not enforce `template\' search path' do
+          expect(template.render).to eq "basic template\n"
+        end
+      end
+    end
+  end
+end