Adds support for :all_or_none option on #import

lib/activerecord-import/import.rb

@@ -254,8 +254,12 @@ class ActiveRecord::Base
         end    
       end
       array_of_attributes.compact!
-      
-      num_inserts = array_of_attributes.empty? ? 0 : import_without_validations_or_callbacks( column_names, array_of_attributes, options )
+
+      num_inserts = if array_of_attributes.empty? || options[:all_or_none] && failed_instances.any?
+                      0
+                    else
+                      import_without_validations_or_callbacks( column_names, array_of_attributes, options )
+                    end
       ActiveRecord::Import::Result.new(failed_instances, num_inserts)
     end
     

test/import_test.rb

@@ -65,7 +65,45 @@ describe "#import" do
       end
     end
   end
-  
+
+  context "with :all_or_none option" do
+    let(:columns) { %w(title author_name) }
+    let(:valid_values) { [[ "LDAP", "Jerry Carter"], ["Rails Recipes", "Chad Fowler"]] }
+    let(:invalid_values) { [[ "The RSpec Book", ""], ["Agile+UX", ""]] }
+    let(:mixed_values) { valid_values + invalid_values }
+
+    context "with validation checks turned on" do
+      it "should import valid data" do
+        assert_difference "Topic.count", +2 do
+          result = Topic.import columns, valid_values, :all_or_none => true
+        end
+      end
+
+      it "should not import invalid data" do
+        assert_no_difference "Topic.count" do
+          result = Topic.import columns, invalid_values, :all_or_none => true
+        end
+      end
+
+      it "should not import valid data when mixed with invalid data" do
+        assert_no_difference "Topic.count" do
+          result = Topic.import columns, mixed_values, :all_or_none => true
+        end
+      end
+
+      it "should report the failed instances" do
+        results = Topic.import columns, mixed_values, :all_or_none => true
+        assert_equal invalid_values.size, results.failed_instances.size
+        results.failed_instances.each { |e| assert_kind_of Topic, e }
+      end
+
+      it "should report the zero inserts" do
+        results = Topic.import columns, mixed_values, :all_or_none => true
+        assert_equal 0, results.num_inserts
+      end
+    end
+  end
+
   context "with :synchronize option" do
     context "synchronizing on new records" do
       let(:new_topics) { Build(3, :topics) }