Add tests for unpermitted param expected behavior

actionpack/test/controller/parameters/raise_on_unpermitted_params_test.rb

@@ -30,4 +30,40 @@ def teardown
       params.permit(book: [:pages])
     end
   end
+
+  test "expect raises on unexpected nested params" do
+    params = ActionController::Parameters.new(
+      book: { pages: 65, title: "Green Cats and where to find then." })
+
+    assert_raises(ActionController::UnpermittedParameters) do
+      params.expect(book: [:pages])
+    end
+  end
+
+  test "expect doesn't raise on unpermitted root params" do
+    params = ActionController::Parameters.new(
+      id: 1,
+      book: { pages: 65, title: "Green Cats and where to find then." })
+
+    params.expect(book: [:pages, :title])
+    params.expect(:id)
+  end
+
+  test "allow raises on unexpected nested params" do
+    params = ActionController::Parameters.new(
+      book: { pages: 65, title: "Green Cats and where to find then." })
+
+    assert_raises(ActionController::UnpermittedParameters) do
+      params.allow(book: [:pages])
+    end
+  end
+
+  test "allow doesn't raise on unpermitted root params" do
+    params = ActionController::Parameters.new(
+      id: 1,
+      book: { pages: 65, title: "Green Cats and where to find then." })
+
+    params.allow(book: [:pages, :title])
+    params.allow(:id)
+  end
 end