1 files changed, 121 insertions, 0 deletions
diff --git a/actionpack/test/controller/parameters/mutators_test.rb b/actionpack/test/controller/parameters/mutators_test.rb
new file mode 100644
index 0000000000..312b1e5b27
--- /dev/null
+++ b/actionpack/test/controller/parameters/mutators_test.rb
@@ -0,0 +1,121 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_controller/metal/strong_parameters"
+
+class ParametersMutatorsTest < ActiveSupport::TestCase
+  setup do
+    @params = ActionController::Parameters.new(
+      person: {
+        age: "32",
+        name: {
+          first: "David",
+          last: "Heinemeier Hansson"
+        },
+        addresses: [{ city: "Chicago", state: "Illinois" }]
+      }
+    )
+  end
+
+  test "delete retains permitted status" do
+    @params.permit!
+    assert_predicate @params.delete(:person), :permitted?
+  end
+
+  test "delete retains unpermitted status" do
+    assert_not_predicate @params.delete(:person), :permitted?
+  end
+
+  test "delete returns the value when the key is present" do
+    assert_equal "32", @params[:person].delete(:age)
+  end
+
+  test "delete removes the entry when the key present" do
+    @params[:person].delete(:age)
+    assert_not @params[:person].key?(:age)
+  end
+
+  test "delete returns nil when the key is not present" do
+    assert_nil @params[:person].delete(:first_name)
+  end
+
+  test "delete returns the value of the given block when the key is not present" do
+    assert_equal "David", @params[:person].delete(:first_name) { "David" }
+  end
+
+  test "delete yields the key to the given block when the key is not present" do
+    assert_equal "first_name: David", @params[:person].delete(:first_name) { |k| "#{k}: David" }
+  end
+
+  test "delete_if retains permitted status" do
+    @params.permit!
+    assert_predicate @params.delete_if { |k| k == "person" }, :permitted?
+  end
+
+  test "delete_if retains unpermitted status" do
+    assert_not_predicate @params.delete_if { |k| k == "person" }, :permitted?
+  end
+
+  test "extract! retains permitted status" do
+    @params.permit!
+    assert_predicate @params.extract!(:person), :permitted?
+  end
+
+  test "extract! retains unpermitted status" do
+    assert_not_predicate @params.extract!(:person), :permitted?
+  end
+
+  test "keep_if retains permitted status" do
+    @params.permit!
+    assert_predicate @params.keep_if { |k, v| k == "person" }, :permitted?
+  end
+
+  test "keep_if retains unpermitted status" do
+    assert_not_predicate @params.keep_if { |k, v| k == "person" }, :permitted?
+  end
+
+  test "reject! retains permitted status" do
+    @params.permit!
+    assert_predicate @params.reject! { |k| k == "person" }, :permitted?
+  end
+
+  test "reject! retains unpermitted status" do
+    assert_not_predicate @params.reject! { |k| k == "person" }, :permitted?
+  end
+
+  test "select! retains permitted status" do
+    @params.permit!
+    assert_predicate @params.select! { |k| k != "person" }, :permitted?
+  end
+
+  test "select! retains unpermitted status" do
+    assert_not_predicate @params.select! { |k| k != "person" }, :permitted?
+  end
+
+  test "slice! retains permitted status" do
+    @params.permit!
+    assert_predicate @params.slice!(:person), :permitted?
+  end
+
+  test "slice! retains unpermitted status" do
+    assert_not_predicate @params.slice!(:person), :permitted?
+  end
+
+  test "transform_keys! retains permitted status" do
+    @params.permit!
+    assert_predicate @params.transform_keys! { |k| k }, :permitted?
+  end
+
+  test "transform_keys! retains unpermitted status" do
+    assert_not_predicate @params.transform_keys! { |k| k }, :permitted?
+  end
+
+  test "transform_values! retains permitted status" do
+    @params.permit!
+    assert_predicate @params.transform_values! { |v| v }, :permitted?
+  end
+
+  test "transform_values! retains unpermitted status" do
+    assert_not_predicate @params.transform_values! { |v| v }, :permitted?
+  end
+end