1 files changed, 52 insertions, 0 deletions
diff --git a/actionpack/test/controller/parameter_encoding_test.rb b/actionpack/test/controller/parameter_encoding_test.rb
new file mode 100644
index 0000000000..e2194e8974
--- /dev/null
+++ b/actionpack/test/controller/parameter_encoding_test.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class ParameterEncodingController < ActionController::Base
+  skip_parameter_encoding :test_bar
+  skip_parameter_encoding :test_all_values_encoding
+
+  def test_foo
+    render body: params[:foo].encoding
+  end
+
+  def test_bar
+    render body: params[:bar].encoding
+  end
+
+  def test_all_values_encoding
+    render body: ::JSON.dump(params.values.map(&:encoding).map(&:name))
+  end
+end
+
+class ParameterEncodingTest < ActionController::TestCase
+  tests ParameterEncodingController
+
+  test "properly transcodes UTF8 parameters into declared encodings" do
+    post :test_foo, params: { "foo" => "foo", "bar" => "bar", "baz" => "baz" }
+
+    assert_response :success
+    assert_equal "UTF-8", @response.body
+  end
+
+  test "properly encodes ASCII_8BIT parameters into binary" do
+    post :test_bar, params: { "foo" => "foo", "bar" => "bar", "baz" => "baz" }
+
+    assert_response :success
+    assert_equal "ASCII-8BIT", @response.body
+  end
+
+  test "properly encodes all ASCII_8BIT parameters into binary" do
+    post :test_all_values_encoding, params: { "foo" => "foo", "bar" => "bar", "baz" => "baz" }
+
+    assert_response :success
+    assert_equal ["ASCII-8BIT"], JSON.parse(@response.body).uniq
+  end
+
+  test "does not raise an error when passed a param declared as ASCII-8BIT that contains invalid bytes" do
+    get :test_bar, params: { "bar" => URI.parser.escape("bar\xE2baz".b) }
+
+    assert_response :success
+    assert_equal "ASCII-8BIT", @response.body
+  end
+end