1 files changed, 24 insertions, 2 deletions

diff --git a/spec/active_relation/unit/predicates/equality_spec.rb b/spec/active_relation/unit/predicates/equality_spec.rb
index 499b13383d..613236ad04 100644
--- a/spec/active_relation/unit/predicates/equality_spec.rb
+++ b/spec/active_relation/unit/predicates/equality_spec.rb
@@ -5,8 +5,8 @@ module ActiveRelation
     before do
       @relation1 = Table.new(:users)
       @relation2 = Table.new(:photos)
-      @attribute1 = @relation1[:name]
-      @attribute2 = @relation2[:name]
+      @attribute1 = @relation1[:id]
+      @attribute2 = @relation2[:user_id]
     end
   
     describe '==' do 
@@ -23,5 +23,27 @@ module ActiveRelation
         Equality.new(@attribute1, @attribute2).should == Equality.new(@attribute2, @attribute1)
       end
     end
+    
+    describe '#to_sql' do
+      describe 'when relating to a non-nil value' do
+        it "manufactures an equality predicate" do
+          Equality.new(@attribute1, @attribute2).to_sql.should be_like("
+            `users`.`id` = `photos`.`user_id`
+          ")
+        end
+      end
+      
+      describe 'when relation to a nil value' do
+        before do
+          @nil = nil.bind(@relation1)
+        end
+        
+        it "manufactures an is null predicate" do
+          Equality.new(@attribute1, @nil).to_sql.should be_like("
+            `users`.`id` IS NULL
+          ")
+        end
+      end
+    end
   end
 end
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