Remove rails_5_x? method

spec/support/unit/helpers/rails_versions.rb

@@ -11,10 +11,6 @@ def rails_version
       Tests::Version.new(Rails::VERSION::STRING)
     end
 
-    def rails_5_x?
-      rails_version =~ '~> 5.0'
-    end
-
     def rails_gte_5_2?
       rails_version >= 5.2
     end

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

@@ -1051,30 +1051,28 @@ def belonging_to_non_existent_class(model_name, assoc_name, options = {})
       }.to fail_with_message(message)
     end
 
-    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)
+    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
 
-        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)'
+        message =
+          'Expected Parent to have a has_many association called children '\
+          '(children should have index_errors set to true)'
 
-          expect {
-            expect(Parent.new).to have_many(:children).index_errors(true)
-          }.to fail_with_message(message)
-        end
+        expect {
+          expect(Parent.new).to have_many(:children).index_errors(true)
+        }.to fail_with_message(message)
       end
     end