1 files changed, 34 insertions, 0 deletions
diff --git a/actionpack/test/controller/params_parse_test.rb b/actionpack/test/controller/params_parse_test.rb
new file mode 100644
index 0000000000..440ab06fd7
--- /dev/null
+++ b/actionpack/test/controller/params_parse_test.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ParamsParseTest < ActionController::TestCase
+  class UsersController < ActionController::Base
+    def create
+      head :ok
+    end
+  end
+
+  tests UsersController
+
+  def test_parse_error_logged_once
+    log_output = capture_log_output do
+      post :create, body: "{", as: :json
+    end
+    assert_equal <<~LOG, log_output
+      Error occurred while parsing request parameters.
+      Contents:
+
+      {
+    LOG
+  end
+
+  private
+
+    def capture_log_output
+      output = StringIO.new
+      request.set_header "action_dispatch.logger", ActiveSupport::Logger.new(output)
+      yield
+      output.string
+    end
+end