1 files changed, 50 insertions, 0 deletions
diff --git a/actionpack/test/controller/parameters/log_on_unpermitted_params_test.rb b/actionpack/test/controller/parameters/log_on_unpermitted_params_test.rb
new file mode 100644
index 0000000000..fb50dabff9
--- /dev/null
+++ b/actionpack/test/controller/parameters/log_on_unpermitted_params_test.rb
@@ -0,0 +1,50 @@
+require 'abstract_unit'
+require 'action_controller/metal/strong_parameters'
+
+class LogOnUnpermittedParamsTest < ActiveSupport::TestCase
+  def setup
+    ActionController::Parameters.action_on_unpermitted = :log
+  end
+
+  def teardown
+    ActionController::Parameters.action_on_unpermitted = false
+  end
+
+  test "logs on unexpected params" do
+    params = ActionController::Parameters.new({
+      book: { pages: 65 },
+      fishing: "Turnips"
+    })
+
+    assert_logged("Unpermitted parameters: fishing") do
+      params.permit(book: [:pages])
+    end
+  end
+
+  test "logs on unexpected nested params" do
+    params = ActionController::Parameters.new({
+      book: { pages: 65, title: "Green Cats and where to find then." }
+    })
+
+    assert_logged("Unpermitted parameters: title") do
+      params.permit(book: [:pages])
+    end
+  end
+
+  private
+
+  def assert_logged(message)
+    old_logger = ActionController::Base.logger
+    log = StringIO.new
+    ActionController::Base.logger = Logger.new(log)
+
+    begin
+      yield
+
+      log.rewind
+      assert_match message, log.read
+    ensure
+      ActionController::Base.logger = old_logger
+    end
+  end
+end
+\ No newline at end of file