1 files changed, 29 insertions, 0 deletions
diff --git a/actionpack/test/controller/parameters/always_permitted_parameters_test.rb b/actionpack/test/controller/parameters/always_permitted_parameters_test.rb
new file mode 100644
index 0000000000..059f310d49
--- /dev/null
+++ b/actionpack/test/controller/parameters/always_permitted_parameters_test.rb
@@ -0,0 +1,29 @@
+require 'abstract_unit'
+require 'action_controller/metal/strong_parameters'
+
+class AlwaysPermittedParametersTest < ActiveSupport::TestCase
+  def setup
+    ActionController::Parameters.action_on_unpermitted_parameters = :raise
+    ActionController::Parameters.always_permitted_parameters = %w( controller action format )
+  end
+
+  def teardown
+    ActionController::Parameters.action_on_unpermitted_parameters = false
+    ActionController::Parameters.always_permitted_parameters = %w( controller action )
+  end
+
+  test "shows deprecations warning on NEVER_UNPERMITTED_PARAMS" do
+    assert_deprecated do
+       ActionController::Parameters::NEVER_UNPERMITTED_PARAMS
+    end
+  end
+
+  test "permits parameters that are whitelisted" do
+    params = ActionController::Parameters.new({
+      book: { pages: 65 },
+      format: "json"
+    })
+    permitted = params.permit book: [:pages]
+    assert permitted.permitted?
+  end
+end