Drop legacy callback matchers under Rails 5

Rails 5 dropped the legacy controller callbacks `before_filter`,
`after_filter` and `around_filter`, so the matchers for these callbacks
are useless.

NEWS.md

@@ -12,6 +12,12 @@ is now:
 * Drop support for Rails 4.0 and 4.1 as well as Ruby 2.0 and 2.1, since they've
   been end-of-lifed. The gem now supports Ruby 2.2+ and Rails 4.2+.
 
+* `use_before_filter`, `use_after_filter`, and `use_around_filter` are no longer
+  usable when using shoulda-matchers under Rails 5.x, as the corresponding
+  controller callback don't exist there.
+
+  * *PR: [#1054]*
+
 ### Bug fixes
 
 * Fix association matchers when used under Rails 5.x so that they make use of
@@ -56,6 +62,7 @@ is now:
 [#964]: https://github.com/thoughtbot/shoulda-matchers/pulls/964
 [#917]: https://github.com/thoughtbot/shoulda-matchers/pulls/917
 [#867]: https://github.com/thoughtbot/shoulda-matchers/issues/867
+[#1054]: https://github.com/thoughtbot/shoulda-matchers/pulls/1054
 
 ### Improvements
 

lib/shoulda/matchers/action_controller/callback_matcher.rb

@@ -20,11 +20,15 @@ module Shoulda
       #       should_not use_before_filter(:prevent_ssl)
       #     end
       #
+      # @note This method is only available when using shoulda-matchers under
+      # Rails 4.x.
       # @return [CallbackMatcher]
       #
+      if RailsShim.action_pack_lt_5?
         def use_before_filter(callback)
           CallbackMatcher.new(callback, :before, :filter)
         end
+      end
 
       # The `use_after_filter` matcher is used to test that an after_filter
       # callback is defined within your controller.
@@ -45,11 +49,15 @@ module Shoulda
       #       should_not use_after_filter(:destroy_user)
       #     end
       #
+      # @note This method is only available when using shoulda-matchers under
+      # Rails 4.x.
       # @return [CallbackMatcher]
       #
+      if RailsShim.action_pack_lt_5?
         def use_after_filter(callback)
           CallbackMatcher.new(callback, :after, :filter)
         end
+      end
 
       # The `use_before_action` matcher is used to test that a before_action
       # callback is defined within your controller.
@@ -120,11 +128,15 @@ module Shoulda
       #       should_not use_around_filter(:save_view_context)
       #     end
       #
+      # @note This method is only available when using shoulda-matchers under
+      # Rails 4.x.
       # @return [CallbackMatcher]
       #
+      if RailsShim.action_pack_lt_5?
         def use_around_filter(callback)
           CallbackMatcher.new(callback, :around, :filter)
         end
+      end
 
       # The `use_around_action` matcher is used to test that an around_action
       # callback is defined within your controller.

lib/shoulda/matchers/rails_shim.rb

@@ -1,7 +1,7 @@
 module Shoulda
   module Matchers
     # @private
-    class RailsShim
+    module RailsShim
       class << self
         def action_pack_gte_4_1?
           Gem::Requirement.new('>= 4.1').satisfied_by?(action_pack_version)
@@ -11,12 +11,20 @@ module Shoulda
           Gem::Requirement.new('>= 5').satisfied_by?(action_pack_version)
         end
 
+        def action_pack_lt_5?
+          Gem::Requirement.new('< 5').satisfied_by?(action_pack_version)
+        end
+
         def action_pack_version
           Gem::Version.new(::ActionPack::VERSION::STRING)
+        rescue NameError
+          Gem::Version.new('0')
         end
 
         def active_record_major_version
           ::ActiveRecord::VERSION::MAJOR
+        rescue NameError
+          Gem::Version.new('0')
         end
 
         def generate_validation_message(

spec/support/unit/helpers/action_pack_versions.rb

@@ -8,7 +8,11 @@ module UnitTests
     end
 
     def action_pack_gte_5?
-      action_pack_version =~ '>= 5'
+      action_pack_version >= 5
+    end
+
+    def action_pack_lt_5?
+      action_pack_version < 5
     end
 
     def action_pack_version

spec/support/unit/helpers/rails_versions.rb

@@ -31,7 +31,7 @@ module UnitTests
       rails_version >= 4.2
     end
 
-    def rails_lte_5?
+    def rails_lt_5?
       rails_version < 5
     end
   end

spec/unit/shoulda/matchers/action_controller/callback_matcher_spec.rb

@@ -54,6 +54,7 @@ describe Shoulda::Matchers::ActionController::CallbackMatcher, type: :controller
     end
   end
 
+  if action_pack_lt_5?
     describe '#use_before_filter' do
       it_behaves_like 'CallbackMatcher', :before, :filter
     end
@@ -65,8 +66,8 @@ describe Shoulda::Matchers::ActionController::CallbackMatcher, type: :controller
     describe '#use_around_filter' do
       it_behaves_like 'CallbackMatcher', :around, :filter
     end
+  end
 
-  if rails_4_x?
   describe '#use_before_action' do
     it_behaves_like 'CallbackMatcher', :before, :action
   end
@@ -79,4 +80,3 @@ describe Shoulda::Matchers::ActionController::CallbackMatcher, type: :controller
     it_behaves_like 'CallbackMatcher', :around, :action
   end
 end
-end

spec/unit/shoulda/matchers/active_model/allow_mass_assignment_of_matcher_spec.rb

@@ -1,7 +1,7 @@
 require 'unit_spec_helper'
 
 describe Shoulda::Matchers::ActiveModel::AllowMassAssignmentOfMatcher, type: :model do
-  if rails_lte_5?
+  if action_pack_lt_5?
     context '#description' do
       context 'without a role' do
         it 'includes the attribute name' do