Put the monkey-patch in a reusable manner so other kaminari-* gems can use this

kaminari-core/test/support/test_unit_rails_triple_nested_sub_test_case.rb

@@ -0,0 +1,19 @@
+# Monkey-patching test-unit-rails not to raise NameError from triple-nested sub_test_case
+ActionView::TestCase.class_eval do
+  class << self
+    def sub_test_case(name, &block)
+      parent_test_case = self
+      sub_test_case = Class.new(self) do
+        singleton_class = class << self; self; end
+        singleton_class.__send__(:define_method, :name) do
+          [parent_test_case.name, name].compact.join("::")
+        end
+        singleton_class.__send__(:define_method, :anonymous?) do
+          true
+        end
+      end
+      sub_test_case.class_eval(&block)
+      sub_test_case
+    end
+  end
+end

test/test_helper.rb

@@ -22,27 +22,3 @@ require 'test/unit/rails/test_help'
 # Requires supporting files with custom matchers and macros, etc,
 # in ./support/ and its subdirectories.
 Dir["#{File.join(Gem.loaded_specs['kaminari-core'].gem_dir, 'test')}/support/**/*.rb"].each {|f| require f}
-
-# Monkey-patching test-unit-rails not to raise NameError from triple-nested sub_test_case
-ActionView::TestCase.class_eval do
-  class << self
-    def sub_test_case(name, &block)
-      parent_test_case = self
-      sub_test_case = Class.new(self) do
-        singleton_class = class << self; self; end
-        singleton_class.__send__(:define_method, :name) do
-          [parent_test_case.name, name].compact.join("::")
-        end
-        singleton_class.__send__(:define_method, :default_helper_module!) do
-          begin
-            super()
-          rescue NameError
-            # Anonymous classes generated via sub_test_case may not always follow Ruby module name convention
-          end
-        end
-      end
-      sub_test_case.class_eval(&block)
-      sub_test_case
-    end
-  end
-end