Implement `file_append' task action

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