From 2065a654e6877b1ac7e815851bc7c4a634fa9644 Mon Sep 17 00:00:00 2001
From: "Ivan Valdes (@ivanvc)" <iv@nvald.es>
Date: Fri, 17 May 2013 13:10:19 -0500
Subject: [PATCH] Fixes validate_uniqueness_of when scope is taken

Re-implement how to get previous value in order to test
validate_uniquenes_of matcher, after the scope changes. This way, new
value should not be taken by a previous record. Fixes #207.
---
 NEWS.md                                       |  3 ++
 .../validate_uniqueness_of_matcher.rb         |  6 +--
 .../validate_uniqueness_of_matcher_spec.rb    | 37 ++++++++++++++++++-
 3 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index bcfb96b5..0d767a9c 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -2,6 +2,9 @@
 
 * Fix `have_and_belong_to_many` matcher issue for Rails 4.
 
+* Fix `validate_uniqueness_of.scoped_to` issue when the scoped field is already
+  taken (#207).
+
 # v 2.1.0
 
 * Add missing `failure_message_for_should_not` implementations to
diff --git a/lib/shoulda/matchers/active_model/validate_uniqueness_of_matcher.rb b/lib/shoulda/matchers/active_model/validate_uniqueness_of_matcher.rb
index 4549e33f..0dbf5297 100644
--- a/lib/shoulda/matchers/active_model/validate_uniqueness_of_matcher.rb
+++ b/lib/shoulda/matchers/active_model/validate_uniqueness_of_matcher.rb
@@ -156,15 +156,13 @@ module Shoulda # :nodoc:
           @existing_record = create_record_in_database
         end
 
-        # TODO:  There is a chance that we could change the scoped field
-        # to a value that's already taken.  An alternative implementation
-        # could actually find all values for scope and create a unique
         def validate_after_scope_change?
           if @options[:scopes].blank?
             true
           else
+            all_records = @subject.class.all
             @options[:scopes].all? do |scope|
-              previous_value = existing_record.send(scope)
+              previous_value = all_records.map(&scope).max
 
               # Assume the scope is a foreign key if the field is nil
               previous_value ||= correct_type_for_column(@subject.class.columns_hash[scope.to_s])
diff --git a/spec/shoulda/matchers/active_model/validate_uniqueness_of_matcher_spec.rb b/spec/shoulda/matchers/active_model/validate_uniqueness_of_matcher_spec.rb
index 52cc0b57..089187af 100644
--- a/spec/shoulda/matchers/active_model/validate_uniqueness_of_matcher_spec.rb
+++ b/spec/shoulda/matchers/active_model/validate_uniqueness_of_matcher_spec.rb
@@ -118,6 +118,13 @@ describe Shoulda::Matchers::ActiveModel::ValidateUniquenessOfMatcher do
           should matcher.scoped_to(:scope1)
       end
 
+      context 'with an existing record that conflicts with scope.next' do
+        it 'accepts' do
+          validating_scoped_uniqueness_with_conflicting_next(:scope1, :date, :scope1 => Date.today).
+            should matcher.scoped_to(:scope1)
+        end
+      end
+
       context 'when too narrow of a scope is specified' do
         it 'rejects' do
           validating_scoped_uniqueness([:scope1, :scope2], :date, :scope1 => Date.today, :scope2 => Date.today).
@@ -132,6 +139,13 @@ describe Shoulda::Matchers::ActiveModel::ValidateUniquenessOfMatcher do
           should matcher.scoped_to(:scope1)
       end
 
+      context 'with an existing record that conflicts with scope.next' do
+        it 'accepts' do
+          validating_scoped_uniqueness_with_conflicting_next(:scope1, :datetime, :scope1 => DateTime.now).
+            should matcher.scoped_to(:scope1)
+        end
+      end
+
       context 'with a nil value' do
         it 'accepts' do
           validating_scoped_uniqueness([:scope1], :datetime, :scope1 => nil).
@@ -145,11 +159,22 @@ describe Shoulda::Matchers::ActiveModel::ValidateUniquenessOfMatcher do
             should_not matcher.scoped_to(:scope1, :scope2, :other)
         end
       end
+
+      context 'with an existing record that conflicts with scope.next' do
+        it 'accepts' do
+          validating_scoped_uniqueness_with_conflicting_next(:scope1, :scope1 => 1).
+            should matcher.scoped_to(:scope1)
+        end
+      end
     end
 
     def create_existing_record(attributes = {})
+      @existing ||= create_record(attributes)
+    end
+
+    def create_record(attributes = {})
       default_attributes = {:attr => 'value', :scope1 => 1, :scope2 => 2, :other => 3}
-      @existing ||= Example.create!(default_attributes.merge(attributes))
+      Example.create!(default_attributes.merge(attributes))
     end
 
     def define_scoped_model(scope, scope_attr_type = :integer)
@@ -166,6 +191,16 @@ describe Shoulda::Matchers::ActiveModel::ValidateUniquenessOfMatcher do
       create_existing_record(attributes)
       model
     end
+
+    def validating_scoped_uniqueness_with_conflicting_next(*args)
+      attributes = args.extract_options!
+      model = define_scoped_model(*args).new
+      2.times do
+        attributes[:scope1] = attributes[:scope1].next
+        create_record(attributes)
+      end
+      model
+    end
   end
 
   context 'a model with a case-sensitive uniqueness validation on a string attribute and an existing record' do