fixup! math class

Author: pirj

spec/rspec/core/memoized_helpers_spec.rb

@@ -340,12 +340,15 @@ def not_ok?; false; end
       end
 
       it 'supports a new expect-based syntax' do
+        math_class = Class.new do
+          def easy?
+            false
+          end
+        end
         group =
-          with_isolated_stderr do
-            RSpec.describe([1, 2, 3]) do
-              it { is_expected.to be_an Array }
-              it { is_expected.not_to include 4 }
-            end
+          RSpec.describe(math_class) do
+            it { is_expected.to be_a math_class }
+            it { is_expected.to_not be_easy }
           end
 
         expect(group.run).to be true