Added support for Ruby 2.4 BigDecimal with empty string.

Starting with Ruby 2.4, BigDecimal.new('') raises an ArgumentError.  Previous
versions returned 0.

Author: Ed Lebert

lib/authorize_net/authorize_net.rb

@@ -1,13 +1,13 @@
 # :title: Authorize.Net Ruby SDK
 # The core AuthoizeNet module. The entire SDK is name-spaced inside of this module.
 module AuthorizeNet
-  
+
   # Some type conversion routines that will be injected into our Transaction/Response
   # classes.
   module TypeConversions
-    
+
     API_FIELD_PREFIX = 'x_'
-    
+
     # Coverts a value received from Authorize.Net into a boolean if possible. This
     # is designed to handle the wide range of boolean formats that Authorize.Net uses.
     def value_to_boolean(value)
@@ -20,7 +20,7 @@ def value_to_boolean(value)
         value
       end
     end
-    
+
     # Converts a boolean into an Authorize.Net boolean value string. This
     # is designed to handle the wide range of boolean formats that Authorize.Net
     # uses. If bool isn't a Boolean, its converted to a string and passed along.
@@ -32,12 +32,13 @@ def boolean_to_value(bool)
         bool.to_s
       end
     end
-    
+
     # Coverts a value received from Authorize.Net into a BigDecimal.
     def value_to_decimal(value)
+      value = 0 if value == '' # Ruby 2.4+ does not accept ""
       BigDecimal.new(value)
     end
-    
+
     # Converts a BigDecimal (or Float) into an Authorize.Net float value string. If float isn't
     # a BigDecimal (or Float), its converted to a string and passed along.
     def decimal_to_value(float)
@@ -50,12 +51,12 @@ def decimal_to_value(float)
         float.to_s
       end
     end
-    
+
     # Coverts a value received from Authorize.Net into a Date.
     def value_to_date(value)
       Date.strptime(value, '%Y-%m-%d')
     end
-    
+
     # Converts a Date (or DateTime, or Time) into an Authorize.Net date value string. If date isn't
     # a Date (or DateTime, or Time), its converted to a string and passed along.
     def date_to_value(date)
@@ -66,12 +67,12 @@ def date_to_value(date)
         date.to_s
       end
     end
-    
+
     # Coverts a value received from Authorize.Net into a DateTime.
     def value_to_datetime(value)
       DateTime.strptime(value, '%Y-%m-%dT%H:%M:%S')
     end
-    
+
     # Converts a Date (or DateTime, or Time) into an Authorize.Net datetime value string. If date isn't
     # a Date (or DateTime, or Time), its converted to a string and passed along.
     def datetime_to_value(datetime)
@@ -84,37 +85,37 @@ def datetime_to_value(datetime)
         datetime.to_s
       end
     end
-    
+
     # Coverts a value received from Authorize.Net into an Integer.
     def value_to_integer(value)
       value.to_s.to_i
     end
-    
+
     # Coverts an Integer into an Authorize.Net integer string.
     def integer_to_value(int)
       int.to_s
     end
-    
+
     # Converts a key value pair into a HTTP POST parameter. The key is prefixed
     # with key_prefix when being converted to a parameter name.
     def to_param(key, value, key_prefix = API_FIELD_PREFIX)
       key_str = "#{key_prefix}#{key}="
-      if value.kind_of?(Array) 
+      if value.kind_of?(Array)
         (value.collect do |v|
           key_str + CGI::escape(v.to_s)
         end).join('&')
       else
         key_str + CGI::escape(value.to_s)
       end
     end
-    
-    
+
+
     # Converts an internal field name (Symbol) into an external field name (Symbol)
     # that can be consumed by the Authorize.Net API.
     def to_external_field(key)
       (API_FIELD_PREFIX + key.to_s).to_sym
     end
-    
+
     # Converts an external field name (Symbol) into an internal field name (Symbol). This
     # is the exact inverse of to_external_field. Running to_internal_field(to_external_field(:foo))
     # would return :foo back.
@@ -123,10 +124,10 @@ def to_internal_field(key)
       k_str[API_FIELD_PREFIX.length..k_str.length].to_sym
     end
   end
-  
+
   # Provides some basic methods used by the various model classes.
   module Model
-    
+
     # The constructor for models. Takes any of the supported attributes
     # as key/value pairs.
     def initialize(fields = {})
@@ -137,18 +138,18 @@ def initialize(fields = {})
         end
       end
     end
-    
+
     def to_a
       [self]
     end
-    
+
     #:enddoc:
     protected
-    
+
     def handle_multivalue_hashing(obj)
       obj.to_a.collect(&:to_hash)
     end
-    
+
   end
 
-end
+end