Add helper methods, tests for registry key path building

Broke out some of the conditional logic in the `#initialize`
method into helper methods and added tests.

Signed-off-by: Adam Leff <adam@leff.co>

lib/resources/registry_key.rb

@@ -63,18 +63,15 @@ module Inspec::Resources
       @options = {}
       if reg_key && reg_key.is_a?(Hash)
         @options = @options.merge!(reg_key)
+
         # generate registry_key if we do not have a regular expression
-        @options[:path] = @options[:hive]
-        # add optional key path
-        if @options[:key]
-          @options[:path] += '\\' if !@options[:key].start_with?('\\')
-          @options[:path] += @options[:key]
-        end
+        @options[:path] = generate_registry_key_path_from_options
         @options[:name] ||= @options[:path]
       else
         @options[:name] = name
         @options[:path] = reg_key
       end
+
       return skip_resource 'The `registry_key` resource is not supported on your OS yet.' if !inspec.os.windows?
     end
 
@@ -258,6 +255,20 @@ module Inspec::Resources
 
       options[symbol]
     end
+
+    def generate_registry_key_path_from_options
+      path = @options[:hive]
+      path += format_key_from_options
+
+      path
+    end
+
+    def format_key_from_options
+      key = @options[:key]
+      return '' unless key
+
+      key.start_with?('\\') ? key : "\\#{key}"
+    end
   end
 
   # for compatability with serverspec

test/unit/resources/registry_key_test.rb

@@ -15,4 +15,23 @@ describe 'Inspec::Resources::RegistryKey' do
     resource_without_name = MockLoader.new(:windows).load_resource('registry_key', 'HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Schedule')
     _(resource_without_name.Start).must_equal 2
   end
+
+  it 'generates a proper path from options' do
+    resource = MockLoader.new(:windows).load_resource(
+      'registry_key',
+      'Test 1',
+      { hive: 'my_hive', key: '\\my_prefixed_key'},
+    )
+    _(resource.send(:generate_registry_key_path_from_options)).must_equal 'my_hive\\my_prefixed_key'
+  end
+
+  it 'generates a proper path from options when the key has no leading slash' do
+    resource = MockLoader.new(:windows).load_resource(
+      'registry_key',
+      'Test 1',
+      { hive: 'my_hive', key: 'key_with_no_slash'},
+    )
+    _(resource.send(:generate_registry_key_path_from_options)).must_equal 'my_hive\\key_with_no_slash'
+  end
+
 end