1 files changed, 3 insertions, 3 deletions
diff --git a/spec/ruby/core/string/shared/partition.rb b/spec/ruby/core/string/shared/partition.rb
index 4cac149ce5..3f7e606eb3 100644
--- a/spec/ruby/core/string/shared/partition.rb
+++ b/spec/ruby/core/string/shared/partition.rb
@@ -4,15 +4,15 @@ require_relative '../fixtures/classes'
 describe :string_partition, shared: true do
   it "returns String instances when called on a subclass" do
     StringSpecs::MyString.new("hello").send(@method, "l").each do |item|
-      item.should be_an_instance_of(String)
+      item.should.instance_of?(String)
     end
 
     StringSpecs::MyString.new("hello").send(@method, "x").each do |item|
-      item.should be_an_instance_of(String)
+      item.should.instance_of?(String)
     end
 
     StringSpecs::MyString.new("hello").send(@method, /l./).each do |item|
-      item.should be_an_instance_of(String)
+      item.should.instance_of?(String)
     end
   end