Implement `file_append' task action

features/actions/file_append.feature

@@ -0,0 +1,17 @@
+@sshd
+Feature: `file_append' task action
+
+  Background:
+    Given a remote file named "some_file" with "some content"
+
+  Scenario: appends given content to requested file
+    Given a recipe with:
+      """
+      target 'some_host.test'
+
+      task :append_content_to_file do
+        file_append 'some_file', ' added'
+      end
+      """
+    When I successfully execute the recipe
+    Then the remote file "some_file" must contain exactly "some content added"

lib/producer/core.rb

@@ -10,6 +10,7 @@ require 'producer/core/action'
 require 'producer/core/actions/echo'
 require 'producer/core/actions/shell_command'
 require 'producer/core/actions/mkdir'
+require 'producer/core/actions/file_append'
 require 'producer/core/actions/file_replace_content'
 require 'producer/core/actions/file_writer'
 

lib/producer/core/actions/file_append.rb

@@ -0,0 +1,23 @@
+module Producer
+  module Core
+    module Actions
+      class FileAppend < Action
+        def apply
+          fs.file_write path, combined_content
+        end
+
+        def path
+          arguments[0]
+        end
+
+        def content
+          arguments[1]
+        end
+
+        def combined_content
+          fs.file_read(path) + content
+        end
+      end
+    end
+  end
+end

lib/producer/core/task/dsl.rb

@@ -13,9 +13,11 @@ module Producer
         define_action :echo,  Actions::Echo
         define_action :sh,    Actions::ShellCommand
 
-        define_action :mkdir,                 Actions::Mkdir
-        define_action :file_write,            Actions::FileWriter
+        define_action :mkdir, Actions::Mkdir
+
+        define_action :file_append,           Actions::FileAppend
         define_action :file_replace_content,  Actions::FileReplaceContent
+        define_action :file_write,            Actions::FileWriter
 
         attr_reader :env, :block, :actions
 

spec/producer/core/actions/file_append_spec.rb

@@ -0,0 +1,42 @@
+require 'spec_helper'
+
+module Producer::Core
+  module Actions
+    describe FileAppend, :env do
+      let(:path)          { 'some_path' }
+      let(:content)       { 'some content' }
+      let(:added_content) { ' added' }
+      subject(:action)    { FileAppend.new(env, path, added_content) }
+
+      it_behaves_like 'action'
+
+      before { allow(remote_fs).to receive(:file_read).with(path) { content } }
+
+      describe '#apply' do
+        it 'appends given content to requested file on remote filesystem' do
+          expect(remote_fs)
+            .to receive(:file_write).with(path, action.combined_content)
+          action.apply
+        end
+      end
+
+      describe '#path' do
+        it 'returns the file path' do
+          expect(action.path).to eq path
+        end
+      end
+
+      describe '#content' do
+        it 'returns the content to append' do
+          expect(action.content).to eq added_content
+        end
+      end
+
+      describe '#combined_content' do
+        it 'returns original content and added content combined' do
+          expect(action.combined_content).to eq 'some content added'
+        end
+      end
+    end
+  end
+end

spec/producer/core/task/dsl_spec.rb

@@ -7,7 +7,14 @@ module Producer::Core
       let(:env)     { Env.new }
       subject(:dsl) { DSL.new(env, &block) }
 
-      %w[echo sh mkdir file_write file_replace_content].each do |action|
+      %w[
+        echo
+        sh
+        mkdir
+        file_append
+        file_replace_content
+        file_write
+      ].each do |action|
         it "has `#{action}' action defined" do
           expect(dsl).to respond_to action.to_sym
         end