1 files changed, 55 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/testing/deprecation.rb b/activesupport/lib/active_support/testing/deprecation.rb
new file mode 100644
index 0000000000..e9220605bd
--- /dev/null
+++ b/activesupport/lib/active_support/testing/deprecation.rb
@@ -0,0 +1,55 @@
+module ActiveSupport
+  module Testing
+    module Deprecation #:nodoc:
+      def assert_deprecated(match = nil, &block)
+        result, warnings = collect_deprecations(&block)
+        assert !warnings.empty?, "Expected a deprecation warning within the block but received none"
+        if match
+          match = Regexp.new(Regexp.escape(match)) unless match.is_a?(Regexp)
+          assert warnings.any? { |w| w =~ match }, "No deprecation warning matched #{match}: #{warnings.join(', ')}"
+        end
+        result
+      end
+
+      def assert_not_deprecated(&block)
+        result, deprecations = collect_deprecations(&block)
+        assert deprecations.empty?, "Expected no deprecation warning within the block but received #{deprecations.size}: \n  #{deprecations * "\n  "}"
+        result
+      end
+
+      private
+        def collect_deprecations
+          old_behavior = ActiveSupport::Deprecation.behavior
+          deprecations = []
+          ActiveSupport::Deprecation.behavior = Proc.new do |message, callstack|
+            deprecations << message
+          end
+          result = yield
+          [result, deprecations]
+        ensure
+          ActiveSupport::Deprecation.behavior = old_behavior
+        end
+    end
+  end
+end
+
+begin
+  require 'test/unit/error'
+
+  module Test
+    module Unit
+      class Error # :nodoc:
+        # Silence warnings when reporting test errors.
+        def message_with_silenced_deprecation
+          ActiveSupport::Deprecation.silence do
+            message_without_silenced_deprecation
+          end
+        end
+
+        alias_method_chain :message, :silenced_deprecation
+      end
+    end
+  end
+rescue LoadError
+  # Using miniunit, ignore.
+end