Add rspec helpers for filesystem

spec/support/filesystem_helpers.rb

@@ -0,0 +1,11 @@
+require 'tempfile'
+
+module FileSystemHelpers
+  def with_file content
+    Tempfile.create('uhwm_rspec') do |f|
+      f.write content
+      f.rewind
+      yield f
+    end
+  end
+end