add memory file and few fixes

library/general/src/lib/config_file/grub_model.rb

@@ -8,6 +8,7 @@ module ConfigFile
   class GrubModel < BaseModel
     def initialize(file_class: File)
       super(PARSER, PATH, file_class: file_class)
+      self.data = {}
     end
 
     def os_prober_enabled?
@@ -37,7 +38,7 @@ def disable_recovery_entry
 
     def enable_recovery_entry(kernel_params)
       data["GRUB_DISABLE_RECOVERY"] ||= {}
-      data["GRUB_DISABLE_RECOVERY"][:value] = "true"
+      data["GRUB_DISABLE_RECOVERY"][:value] = "false"
       data["GRUB_DISABLE_RECOVERY"][:commented_out] = false
       data["GRUB_CMDLINE_LINUX_RECOVERY"] ||= {}
       data["GRUB_CMDLINE_LINUX_RECOVERY"][:value] = kernel_params

library/general/src/lib/config_file/key_value_parser.rb

@@ -26,8 +26,10 @@ def self.parse(raw_string)
     def self.serialize(data)
       data.each_with_object("") do |pair, res|
         key, content = pair
-        content[:comments].each do |comment|
-          res << "# #{comment}\n"
+        if content[:comments]
+          content[:comments].each do |comment|
+            res << "# #{comment}\n"
+          end
         end
         prefix = content[:commented_out] ? "#" : ""
         res << "#{prefix}#{key}=#{content[:value]}\n"

library/general/src/lib/config_file/memory_file.rb

@@ -0,0 +1,17 @@
+module ConfigFile
+  class MemoryFile
+    attr_accessor :content
+
+    def initialize(content = "")
+      @content = content
+    end
+
+    def read(path)
+      @content.dup
+    end
+
+    def write(path, content)
+      @content = content
+    end
+  end
+end