we still need `describe` as the implementation differs from minitest

activesupport/lib/active_support/test_case.rb

@@ -3,6 +3,7 @@
 require 'active_support/testing/setup_and_teardown'
 require 'active_support/testing/assertions'
 require 'active_support/testing/deprecation'
+require 'active_support/testing/declarative'
 require 'active_support/testing/isolation'
 require 'active_support/testing/mocha_module'
 require 'active_support/core_ext/kernel/reporting'
@@ -34,6 +35,7 @@ def self.test_order # :nodoc:
     include ActiveSupport::Testing::SetupAndTeardown
     include ActiveSupport::Testing::Assertions
     include ActiveSupport::Testing::Deprecation
+    extend ActiveSupport::Testing::Declarative
 
     class << self
       alias :test :it

activesupport/lib/active_support/testing/declarative.rb

+module ActiveSupport
+  module Testing
+    module Declarative
+
+      def self.extended(klass) #:nodoc:
+        klass.class_eval do
+
+          unless method_defined?(:describe)
+            def self.describe(text)
+              class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1
+                def self.name
+                  "#{text}"
+                end
+              RUBY_EVAL
+            end
+          end
+
+        end
+      end
+    end
+  end
+end