fix #1268 and allows registry key resource with leading backslash

Signed-off-by: Christoph Hartmann <chris@lollyrock.com>

lib/resources/registry_key.rb

@@ -66,7 +66,10 @@ module Inspec::Resources
         # generate registry_key if we do not have a regular expression
         @options[:path] = @options[:hive]
         # add optional key path
-        @options[:path] += '\\' + @options[:key] if @options[:key]
+        if @options[:key]
+          @options[:path] += '\\' if !@options[:key].start_with?('\\')
+          @options[:path] += @options[:key]
+        end
         @options[:name] ||= @options[:path]
       else
         @options[:name] = name

test/integration/default/registry_key_spec.rb

@@ -111,3 +111,21 @@ control 'regex-test' do
     end
   }
 end
+
+# test key without leading slash
+describe registry_key({
+  hive: 'HKLM',
+  key:  'System\Test',
+}) do
+  it { should exist }
+  it { should have_value('test') }
+end
+
+# test key with leading slash
+describe registry_key({
+  hive: 'HKLM',
+  key:  '\System\Test',
+}) do
+  it { should exist }
+  it { should have_value('test') }
+end