support for validates_length_of

README.markdown

@@ -117,6 +117,13 @@ validates_inclusion_of
 SampleModels will set the attribute to one of the specified values.
 
 
+validates_length_of
+-------------------
+
+SampleModels will set the attribute to a string within the specified
+length constraints.
+
+
 validates_uniqueness_of
 -----------------------
 

lib/sample_models/attribute_sequence.rb

@@ -27,6 +27,8 @@ def self.source(pass, model, column, force_email_format)
         EmailSource.new
       elsif v = validations.detect(&:inclusion?)
         InclusionSource.new(v)
+      elsif v = validations.detect(&:length?)
+        LengthSource.new(v)
       else
         SimpleSource.new(column)
       end
@@ -65,6 +67,29 @@ def value
         @validation.config[:in].first
       end
     end
+
+    class LengthSource < AbstractSource
+      def initialize(validation)
+        super()
+        @validation = validation
+      end
+
+      def value
+        minimum = @validation.config[:minimum]
+        minimum ||= (
+          @validation.config[:within] && @validation.config[:within].begin
+        )
+        minimum ||= (
+          @validation.config[:in] && @validation.config[:in].begin
+        )
+        minimum ||= 1
+        value = 'a' * minimum
+        @number.times do
+          value = value.succ
+        end
+        value
+      end
+    end
 
     class RequiredBelongsToSource < AbstractSource
       def initialize(assoc)

lib/sample_models/initializer.rb

@@ -17,7 +17,7 @@ def intercept_validation_definition(validation, recipient)
     def intercept_validation_definitions
       validations_to_intercept = [
         :validates_email_format_of, :validates_inclusion_of,
-        :validates_presence_of, :validates_uniqueness_of
+        :validates_length_of, :validates_presence_of, :validates_uniqueness_of
       ]
       optional_interceptions = [:validates_email_format_of]
       validations_to_intercept.each do |validation|

lib/sample_models/model.rb

@@ -88,21 +88,16 @@ class Validation
       def initialize(type, config = {})
         @type, @config = type, config
       end
-
-      def email_format?
-        @type == :validates_email_format_of
-      end
-
-      def inclusion?
-        @type == :validates_inclusion_of
-      end
-
-      def presence?
-        @type == :validates_presence_of
-      end
 
-      def uniqueness?
-        @type == :validates_uniqueness_of
+      def method_missing(meth, *args, &block)
+        type_predicates = %w(
+          email_format? inclusion? length? presence? uniqueness?
+        )
+        if type_predicates.include?(meth.to_s)
+          @type == "validates_#{meth.to_s.chop}_of".to_sym
+        else
+          super
+        end
       end
     end
   end

test/setup/models.rb

@@ -99,6 +99,11 @@ class User < ActiveRecord::Base
 class User2 < ActiveRecord::Base
   validates_presence_of   :login
   validates_uniqueness_of :login
+  validates_length_of     :token1, :minimum => 40
+  validates_length_of     :token2, :maximum => 4
+  validates_uniqueness_of :token2
+  validates_length_of     :token3, :within => (20..40)
+  validates_length_of     :token4, :in => (20..40)
 end
 
 class UserWithPassword < ActiveRecord::Base

test/setup/schema.rb

@@ -89,6 +89,10 @@
     create_table 'user2s', :force => true do |user2|
       user2.string  'login'
       user2.string  'email'
+      user2.string  'token1'
+      user2.string  'token2'
+      user2.string  'token3'
+      user2.string  'token4'
     end
 
     create_table 'user_with_passwords', :force => true do |user|

test/unit/sample_test.rb

@@ -90,7 +90,10 @@ def test_required_accessor
   def test_string_which_is_required_to_be_present_and_unique
     # Ensuring that it doesn't get tripped up by a pre-existing record
     User2.destroy_all
-    User2.create!(:login => 'login 1')
+    User2.create!(
+      :login => 'login 1', :token1 => 'a' * 40, :token2 => 'a' * 4,
+      :token3 => 'a' * 20, :token4 => 'a' * 20
+    )
     User2.sample
   end
 

test/unit/validations_test.rb

@@ -27,5 +27,18 @@ def test_cant_override_validations
       end
     end
   end
+
+  def test_validates_length_of
+    token2s = []
+    50.times do
+      user2 = User2.sample
+      assert(user2.token1.length >= 40)
+      assert(user2.token2.length <= 4)
+      token2s << user2.token2
+      assert(user2.token3.length >= 20 && user2.token3.length <= 40)
+      assert(user2.token4.length >= 20 && user2.token4.length <= 40)
+    end
+    assert_equal(token2s.size, token2s.uniq.size)
+  end
 end