1 files changed, 32 insertions, 9 deletions
diff --git a/actionpack/test/controller/parameters/mutators_test.rb b/actionpack/test/controller/parameters/mutators_test.rb
index 744d8664be..49dede03c2 100644
--- a/actionpack/test/controller/parameters/mutators_test.rb
+++ b/actionpack/test/controller/parameters/mutators_test.rb
@@ -1,17 +1,19 @@
-require 'abstract_unit'
-require 'action_controller/metal/strong_parameters'
-require 'active_support/core_ext/hash/transform_values'
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "action_controller/metal/strong_parameters"
+require "active_support/core_ext/hash/transform_values"
 
 class ParametersMutatorsTest < ActiveSupport::TestCase
   setup do
     @params = ActionController::Parameters.new(
       person: {
-        age: '32',
+        age: "32",
         name: {
-          first: 'David',
-          last: 'Heinemeier Hansson'
+          first: "David",
+          last: "Heinemeier Hansson"
         },
-        addresses: [{city: 'Chicago', state: 'Illinois'}]
+        addresses: [{ city: "Chicago", state: "Illinois" }]
       }
     )
   end
@@ -25,6 +27,27 @@ class ParametersMutatorsTest < ActiveSupport::TestCase
     assert_not @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 @params.delete_if { |k| k == "person" }.permitted?
@@ -45,11 +68,11 @@ class ParametersMutatorsTest < ActiveSupport::TestCase
 
   test "keep_if retains permitted status" do
     @params.permit!
-    assert @params.keep_if { |k,v| k == "person" }.permitted?
+    assert @params.keep_if { |k, v| k == "person" }.permitted?
   end
 
   test "keep_if retains unpermitted status" do
-    assert_not @params.keep_if { |k,v| k == "person" }.permitted?
+    assert_not @params.keep_if { |k, v| k == "person" }.permitted?
   end
 
   test "reject! retains permitted status" do