Provide a config option to debug failures

lib/vagrant-spec/acceptance/configuration.rb

@@ -37,6 +37,12 @@ class Configuration
         # different depending on mode.
         attr_accessor :run_mode
 
+        # Remove isolated environment on example failure. By default this
+        # is set to be true, but can be disabled by setting to false which
+        # will result in teardown skipping removal and messaging the output
+        # as to the paths retained.
+        attr_accessor :clean_on_fail
+
         def initialize
           @component_paths = [
             Vagrant::Spec.source_root.join("acceptance"),
@@ -48,6 +54,7 @@ def initialize
           @skeleton_paths = []
           @vagrant_path   = "vagrant"
           @run_mode       = "standalone"
+          @clean_on_fail  = true
         end
 
         # Tells vagrant-spec to acceptance test a certain provider.

lib/vagrant-spec/acceptance/rspec/context.rb

@@ -23,8 +23,12 @@
     config.skeleton_paths.dup.unshift(root)
   end
 
-  after(:each) do
-    environment.close
+  after(:each) do |example|
+    if example.exception.nil? || config.clean_on_fail
+      environment.close
+    else
+      example.reporter.message("Temporary work and home dirs (#{environment.workdir} and #{environment.homedir}) not removed to allow debug")
+    end
   end
 
   # Creates a new isolated environment instance each time it is called.