Begin to add Numeric class helper for converting size strings

lib/vagrant/util/numeric.rb

@@ -0,0 +1,37 @@
+module Vagrant
+  module Util
+    class Numeric
+      # Authors Note: This class has borrowed some code from the ActiveSupport Numeric class
+
+      # Conversion helper constants
+      KILOBYTE = 1024
+      MEGABYTE = KILOBYTE * 1024
+      GIGABYTE = MEGABYTE * 1024
+      TERABYTE = GIGABYTE * 1024
+      PETABYTE = TERABYTE * 1024
+      EXABYTE  = PETABYTE * 1024
+
+      class << self
+
+        # A helper that converts a shortcut string to its bytes representation.
+        # The expected format of `str` is essentially: "<Number>XX"
+        # Where `XX` is shorthand for KB, MB, GB, TB, PB, or EB. For example, 50 megabytes:
+        #
+        # str = "50MB"
+        #
+        # @param [String] - str
+        # @return [Integer] - bytes
+        def string_to_bytes(str)
+          str = str.to_s.strip
+        end
+
+        # @private
+        # Reset the cached values for platform. This is not considered a public
+        # API and should only be used for testing.
+        def reset!
+          instance_variables.each(&method(:remove_instance_variable))
+        end
+      end
+    end
+  end
+end

plugins/kernel_v2/config/disk.rb

@@ -1,6 +1,8 @@
 require "log4r"
 require "securerandom"
 
+require "vagrant/util/numeric"
+
 module VagrantPlugins
   module Kernel_V2
     class VagrantConfigDisk < Vagrant.plugin("2", :config)
@@ -124,9 +126,12 @@ module VagrantPlugins
           errors << "Disk type '#{@type}' is not a valid type. Please pick one of the following supported disk types: #{DEFAULT_DISK_TYPES.join(', ')}"
         end
 
-        # TODO: Convert a string to int here?
         if @size && !@size.is_a?(Integer)
-          errors << "Config option size for disk is not an integer"
+          if @size.is_a?(String)
+            @size = Vagrant::Util::Numeric.string_to_bytes(@size)
+          else
+            errors << "Config option size for disk is not an integer"
+          end
         end
 
         if @file