diff --git a/spec/support/unit/helpers/rails_versions.rb b/spec/support/unit/helpers/rails_versions.rb
index 5ac1562c..61b233a6 100644
--- a/spec/support/unit/helpers/rails_versions.rb
+++ b/spec/support/unit/helpers/rails_versions.rb
@@ -30,5 +30,9 @@ module UnitTests
     def rails_gte_4_2?
       rails_version >= 4.2
     end
+
+    def rails_lte_5?
+      rails_version < 5
+    end
   end
 end
diff --git a/spec/unit/shoulda/matchers/active_model/allow_mass_assignment_of_matcher_spec.rb b/spec/unit/shoulda/matchers/active_model/allow_mass_assignment_of_matcher_spec.rb
index 175aec92..f53c82e6 100644
--- a/spec/unit/shoulda/matchers/active_model/allow_mass_assignment_of_matcher_spec.rb
+++ b/spec/unit/shoulda/matchers/active_model/allow_mass_assignment_of_matcher_spec.rb
@@ -1,115 +1,117 @@
 require 'unit_spec_helper'
 
 describe Shoulda::Matchers::ActiveModel::AllowMassAssignmentOfMatcher, type: :model do
-  context '#description' do
-    context 'without a role' do
-      it 'includes the attribute name' do
-        expect(described_class.new(:attr).description).
-          to eq 'allow mass assignment of attr'
+  if rails_lte_5?
+    context '#description' do
+      context 'without a role' do
+        it 'includes the attribute name' do
+          expect(described_class.new(:attr).description).
+            to eq 'allow mass assignment of attr'
+        end
+      end
+
+      if active_model_3_1?
+        context 'with a role' do
+          it 'includes the attribute name and the role' do
+            expect(described_class.new(:attr).as(:admin).description).
+              to eq 'allow mass assignment of attr as admin'
+          end
+        end
+      end
+    end
+
+    context 'an attribute that is blacklisted from mass-assignment' do
+      it 'rejects being mass-assignable' do
+        model = define_model(:example, blacklisted: :string) do
+          attr_protected :blacklisted
+        end.new
+
+        expect(model).not_to allow_mass_assignment_of(:blacklisted)
+      end
+    end
+
+    context 'an attribute that is not whitelisted for mass-assignment' do
+      it 'rejects being mass-assignable' do
+        model = define_model(:example, not_whitelisted: :string,
+          whitelisted: :string) do
+          attr_accessible :whitelisted
+        end.new
+
+        expect(model).not_to allow_mass_assignment_of(:not_whitelisted)
+      end
+    end
+
+    context 'an attribute that is whitelisted for mass-assignment' do
+      it 'accepts being mass-assignable' do
+        expect(define_model(:example, whitelisted: :string) do
+          attr_accessible :whitelisted
+        end.new).to allow_mass_assignment_of(:whitelisted)
+      end
+    end
+
+    context 'an attribute not included in the mass-assignment blacklist' do
+      it 'accepts being mass-assignable' do
+        model = define_model(:example, not_blacklisted: :string,
+          blacklisted: :string) do
+          attr_protected :blacklisted
+        end.new
+
+        expect(model).to allow_mass_assignment_of(:not_blacklisted)
+      end
+    end
+
+    unless active_model_3_2? || active_model_4_0?
+      context 'an attribute on a class with no protected attributes' do
+        it 'accepts being mass-assignable' do
+          expect(no_protected_attributes).to allow_mass_assignment_of(:attr)
+        end
+
+        it 'assigns a negative failure message' do
+          matcher = allow_mass_assignment_of(:attr)
+
+          expect(matcher.matches?(no_protected_attributes)).to eq true
+
+          expect(matcher.failure_message_when_negated).not_to be_nil
+        end
+      end
+
+      def no_protected_attributes
+        define_model(:example, attr: :string).new
+      end
+    end
+
+    context 'an attribute on a class with all protected attributes' do
+      it 'rejects being mass-assignable' do
+        expect(all_protected_attributes).not_to allow_mass_assignment_of(:attr)
+      end
+
+      def all_protected_attributes
+        define_model(:example, attr: :string) do
+          attr_accessible nil
+        end.new
       end
     end
 
     if active_model_3_1?
-      context 'with a role' do
-        it 'includes the attribute name and the role' do
-          expect(described_class.new(:attr).as(:admin).description).
-            to eq 'allow mass assignment of attr as admin'
+      context 'an attribute included in the mass-assignment whitelist for admin role only' do
+        it 'rejects being mass-assignable' do
+          expect(mass_assignable_as_admin).not_to allow_mass_assignment_of(:attr)
+        end
+
+        it 'accepts being mass-assignable for admin' do
+          expect(mass_assignable_as_admin).to allow_mass_assignment_of(:attr).as(:admin)
+        end
+
+        def mass_assignable_as_admin
+          define_model(:example, attr: :string) do
+            attr_accessible :attr, as: :admin
+          end.new
         end
       end
     end
-  end
 
-  context 'an attribute that is blacklisted from mass-assignment' do
-    it 'rejects being mass-assignable' do
-      model = define_model(:example, blacklisted: :string) do
-        attr_protected :blacklisted
-      end.new
-
-      expect(model).not_to allow_mass_assignment_of(:blacklisted)
+    def define_model(name, columns, &block)
+      super(name, columns, whitelist_attributes: false, &block)
     end
   end
-
-  context 'an attribute that is not whitelisted for mass-assignment' do
-    it 'rejects being mass-assignable' do
-      model = define_model(:example, not_whitelisted: :string,
-        whitelisted: :string) do
-        attr_accessible :whitelisted
-      end.new
-
-      expect(model).not_to allow_mass_assignment_of(:not_whitelisted)
-    end
-  end
-
-  context 'an attribute that is whitelisted for mass-assignment' do
-    it 'accepts being mass-assignable' do
-      expect(define_model(:example, whitelisted: :string) do
-        attr_accessible :whitelisted
-      end.new).to allow_mass_assignment_of(:whitelisted)
-    end
-  end
-
-  context 'an attribute not included in the mass-assignment blacklist' do
-    it 'accepts being mass-assignable' do
-      model = define_model(:example, not_blacklisted: :string,
-        blacklisted: :string) do
-        attr_protected :blacklisted
-      end.new
-
-      expect(model).to allow_mass_assignment_of(:not_blacklisted)
-    end
-  end
-
-  unless active_model_3_2? || active_model_4_0?
-    context 'an attribute on a class with no protected attributes' do
-      it 'accepts being mass-assignable' do
-        expect(no_protected_attributes).to allow_mass_assignment_of(:attr)
-      end
-
-      it 'assigns a negative failure message' do
-        matcher = allow_mass_assignment_of(:attr)
-
-        expect(matcher.matches?(no_protected_attributes)).to eq true
-
-        expect(matcher.failure_message_when_negated).not_to be_nil
-      end
-    end
-
-    def no_protected_attributes
-      define_model(:example, attr: :string).new
-    end
-  end
-
-  context 'an attribute on a class with all protected attributes' do
-    it 'rejects being mass-assignable' do
-      expect(all_protected_attributes).not_to allow_mass_assignment_of(:attr)
-    end
-
-    def all_protected_attributes
-      define_model(:example, attr: :string) do
-        attr_accessible nil
-      end.new
-    end
-  end
-
-  if active_model_3_1?
-    context 'an attribute included in the mass-assignment whitelist for admin role only' do
-      it 'rejects being mass-assignable' do
-        expect(mass_assignable_as_admin).not_to allow_mass_assignment_of(:attr)
-      end
-
-      it 'accepts being mass-assignable for admin' do
-        expect(mass_assignable_as_admin).to allow_mass_assignment_of(:attr).as(:admin)
-      end
-
-      def mass_assignable_as_admin
-        define_model(:example, attr: :string) do
-          attr_accessible :attr, as: :admin
-        end.new
-      end
-    end
-  end
-
-  def define_model(name, columns, &block)
-    super(name, columns, whitelist_attributes: false, &block)
-  end
 end