1 files changed, 20 insertions, 0 deletions
diff --git a/activesupport/test/json/encoding_test.rb b/activesupport/test/json/encoding_test.rb
index fc3af02cbc..fa518104c2 100644
--- a/activesupport/test/json/encoding_test.rb
+++ b/activesupport/test/json/encoding_test.rb
@@ -432,6 +432,26 @@ EXPECTED
     assert_equal '"foo"', ActiveSupport::JSON.encode(exception)
   end
 
+  class InfiniteNumber
+    def as_json(options = nil)
+      { "number" => Float::INFINITY }
+    end
+  end
+
+  def test_to_json_works_when_as_json_returns_infinite_number
+    assert_equal '{"number":null}', InfiniteNumber.new.to_json
+  end
+
+  class NaNNumber
+    def as_json(options = nil)
+      { "number" => Float::NAN }
+    end
+  end
+
+  def test_to_json_works_when_as_json_returns_NaN_number
+    assert_equal '{"number":null}', NaNNumber.new.to_json
+  end
+
   protected
 
     def object_keys(json_object)