3 files changed, 20 insertions, 6 deletions
diff --git a/activesupport/test/json/decoding_test.rb b/activesupport/test/json/decoding_test.rb
index 6f5051c312..8d9587f248 100644
--- a/activesupport/test/json/decoding_test.rb
+++ b/activesupport/test/json/decoding_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "abstract_unit"
 require "active_support/json"
 require "active_support/time"
diff --git a/activesupport/test/json/encoding_test.rb b/activesupport/test/json/encoding_test.rb
index 6d8f7cfbd0..340a2abf75 100644
--- a/activesupport/test/json/encoding_test.rb
+++ b/activesupport/test/json/encoding_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "securerandom"
 require "abstract_unit"
 require "active_support/core_ext/string/inflections"
@@ -98,11 +100,11 @@ class TestJSONEncoding < ActiveSupport::TestCase
   end
 
   def test_hash_should_allow_key_filtering_with_only
-    assert_equal %({"a":1}), ActiveSupport::JSON.encode({ "a" => 1, :b => 2, :c => 3 }, only: "a")
+    assert_equal %({"a":1}), ActiveSupport::JSON.encode({ "a" => 1, :b => 2, :c => 3 }, { only: "a" })
   end
 
   def test_hash_should_allow_key_filtering_with_except
-    assert_equal %({"b":2}), ActiveSupport::JSON.encode({ "foo" => "bar", :b => 2, :c => 3 }, except: ["foo", :c])
+    assert_equal %({"b":2}), ActiveSupport::JSON.encode({ "foo" => "bar", :b => 2, :c => 3 }, { except: ["foo", :c] })
   end
 
   def test_time_to_json_includes_local_offset
@@ -185,7 +187,7 @@ class TestJSONEncoding < ActiveSupport::TestCase
   def test_array_should_pass_encoding_options_to_children_in_as_json
     people = [
       { name: "John", address: { city: "London", country: "UK" } },
-      { name: "Jean", address: { city: "Paris" , country: "France" } }
+      { name: "Jean", address: { city: "Paris", country: "France" } }
     ]
     json = people.as_json only: [:address, :city]
     expected = [
@@ -199,7 +201,7 @@ class TestJSONEncoding < ActiveSupport::TestCase
   def test_array_should_pass_encoding_options_to_children_in_to_json
     people = [
       { name: "John", address: { city: "London", country: "UK" } },
-      { name: "Jean", address: { city: "Paris" , country: "France" } }
+      { name: "Jean", address: { city: "Paris", country: "France" } }
     ]
     json = people.to_json only: [:address, :city]
 
@@ -208,10 +210,10 @@ class TestJSONEncoding < ActiveSupport::TestCase
 
   People = Class.new(BasicObject) do
     include Enumerable
-    def initialize()
+    def initialize
       @people = [
         { name: "John", address: { city: "London", country: "UK" } },
-        { name: "Jean", address: { city: "Paris" , country: "France" } }
+        { name: "Jean", address: { city: "Paris", country: "France" } }
       ]
     end
     def each(*, &blk)
@@ -452,6 +454,10 @@ EXPECTED
     assert_equal '{"number":null}', NaNNumber.new.to_json
   end
 
+  def test_to_json_works_on_io_objects
+    assert_equal STDOUT.to_s.to_json, STDOUT.to_json
+  end
+
   private
 
     def object_keys(json_object)
diff --git a/activesupport/test/json/encoding_test_cases.rb b/activesupport/test/json/encoding_test_cases.rb
index b2f0cf3048..5a4700459f 100644
--- a/activesupport/test/json/encoding_test_cases.rb
+++ b/activesupport/test/json/encoding_test_cases.rb
@@ -1,4 +1,10 @@
+# frozen_string_literal: true
+
 require "bigdecimal"
+require "date"
+require "time"
+require "pathname"
+require "uri"
 
 module JSONTest
   class Foo