only run specs for >= rails 5

lib/shoulda/matchers/active_record/association_matcher.rb

@@ -1284,8 +1284,9 @@ def autosave_correct?
 
         def index_errors_correct?
           if options.key?(:index_errors)
-            if option_verifier.correct_for_boolean?(:index_errors,
-                                                    options[:index_errors])
+            if option_verifier.correct_for_boolean?(
+                :index_errors, options[:index_errors]
+            )
               true
             else
               @missing = "#{name} should have index_errors set to "\

spec/support/unit/helpers/rails_versions.rb

@@ -34,5 +34,9 @@ def rails_gte_4_2?
     def rails_lt_5?
       rails_version < 5
     end
+
+    def rails_5_x?
+      rails_version =~ '~> 5.0'
+    end
   end
 end

spec/unit/shoulda/matchers/active_record/association_matcher_spec.rb

@@ -801,27 +801,29 @@ def belonging_to_non_existent_class(model_name, assoc_name, options = {})
       }.to fail_with_message(message)
     end
 
-    context 'index_errors' do
-      it 'accepts an association with a matching :index_errors option' do
-        define_model :child, parent_id: :integer
-        define_model :parent do
-          has_many :children, index_errors: true
+    if rails_5_x?
+      context 'index_errors' do
+        it 'accepts an association with a matching :index_errors option' do
+          define_model :child, parent_id: :integer
+          define_model :parent do
+            has_many :children, index_errors: true
+          end
+          expect(Parent.new).to have_many(:children).index_errors(true)
         end
-        expect(Parent.new).to have_many(:children).index_errors(true)
-      end
 
-      it 'rejects an association with a non-matching :index_errors option and '\
-         'returns the correct message' do
-        define_model :child, parent_id: :integer
-        define_model :parent do
-          has_many :children, autosave: false
-        end
+        it 'rejects an association with a non-matching :index_errors option '\
+           'and returns the correct message' do
+          define_model :child, parent_id: :integer
+          define_model :parent do
+            has_many :children, autosave: false
+          end
 
-        message = 'Expected Parent to have a has_many association called '\
-                  'children (children should have index_errors set to true)'
-        expect do
-          expect(Parent.new).to have_many(:children).index_errors(true)
-        end.to fail_with_message(message)
+          message = 'Expected Parent to have a has_many association called '\
+                    'children (children should have index_errors set to true)'
+          expect do
+            expect(Parent.new).to have_many(:children).index_errors(true)
+          end.to fail_with_message(message)
+        end
       end
     end