1 files changed, 3 insertions, 2 deletions
diff --git a/spec/ruby/core/string/element_set_spec.rb b/spec/ruby/core/string/element_set_spec.rb
index 881b4343d4..e7599f832c 100644
--- a/spec/ruby/core/string/element_set_spec.rb
+++ b/spec/ruby/core/string/element_set_spec.rb
@@ -1,4 +1,5 @@
 # -*- encoding: utf-8 -*-
+# frozen_string_literal: false
 require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
 
@@ -357,11 +358,11 @@ describe "String#[]= with a Range index" do
   end
 
   it "raises a RangeError if negative Range begin is out of range" do
-    -> { "abc"[-4..-2] = "x" }.should raise_error(RangeError)
+    -> { "abc"[-4..-2] = "x" }.should raise_error(RangeError, "-4..-2 out of range")
   end
 
   it "raises a RangeError if positive Range begin is greater than String size" do
-    -> { "abc"[4..2] = "x" }.should raise_error(RangeError)
+    -> { "abc"[4..2] = "x" }.should raise_error(RangeError, "4..2 out of range")
   end
 
   it "uses the Range end as an index rather than a count" do