Forward standard error stream from remote execution

features/action_sh.feature

@@ -11,6 +11,16 @@ Feature: `sh' task action
     When I successfully execute the recipe on remote target
     Then the output must contain exactly "hello from remote\n"
 
+  Scenario: forwards error ouput
+    Given a recipe with:
+      """
+      task :sh_action do
+        sh '\echo error from remote >&2'
+      end
+      """
+    When I successfully execute the recipe on remote target
+    Then the error output must contain exactly "error from remote\n"
+
   Scenario: aborts on failed command execution
     Given a recipe with:
       """

features/steps/output_steps.rb

@@ -21,3 +21,7 @@ end
 Then /^the output must contain exactly:$/ do |content|
   assert_exact_output content, all_output
 end
+
+Then /^the error output must contain exactly "([^"]+)"$/ do |content|
+  assert_exact_output content, all_stderr
+end