1 files changed, 15 insertions, 22 deletions
diff --git a/spec/ruby/core/string/delete_prefix_spec.rb b/spec/ruby/core/string/delete_prefix_spec.rb
index 8469791f74..fc69adcbad 100644
--- a/spec/ruby/core/string/delete_prefix_spec.rb
+++ b/spec/ruby/core/string/delete_prefix_spec.rb
@@ -1,4 +1,5 @@
 # -*- encoding: utf-8 -*-
+# frozen_string_literal: false
 require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
 
@@ -11,21 +12,18 @@ describe "String#delete_prefix" do
   it "returns a copy of the string, when the prefix isn't found" do
     s = 'hello'
     r = s.delete_prefix('hello!')
-    r.should_not equal s
+    r.should_not.equal? s
     r.should == s
     r = s.delete_prefix('ell')
-    r.should_not equal s
+    r.should_not.equal? s
     r.should == s
     r = s.delete_prefix('')
-    r.should_not equal s
+    r.should_not.equal? s
     r.should == s
   end
 
-  ruby_version_is ''...'2.7' do
-    it "taints resulting strings when other is tainted" do
-      'hello'.taint.delete_prefix('hell').should.tainted?
-      'hello'.taint.delete_prefix('').should.tainted?
-    end
+  it "does not remove partial bytes, only full characters" do
+    "\xe3\x81\x82".delete_prefix("\xe3").should == "\xe3\x81\x82"
   end
 
   it "doesn't set $~" do
@@ -41,25 +39,20 @@ describe "String#delete_prefix" do
     'hello'.delete_prefix(o).should == 'o'
   end
 
-  ruby_version_is ''...'3.0' do
-    it "returns a subclass instance when called on a subclass instance" do
-      s = StringSpecs::MyString.new('hello')
-      s.delete_prefix('hell').should be_an_instance_of(StringSpecs::MyString)
-    end
+  it "returns a String instance when called on a subclass instance" do
+    s = StringSpecs::MyString.new('hello')
+    s.delete_prefix('hell').should.instance_of?(String)
   end
 
-  ruby_version_is '3.0' do
-    it "returns a String instance when called on a subclass instance" do
-      s = StringSpecs::MyString.new('hello')
-      s.delete_prefix('hell').should be_an_instance_of(String)
-    end
+  it "returns a String in the same encoding as self" do
+    'hello'.encode("US-ASCII").delete_prefix('hell').encoding.should == Encoding::US_ASCII
   end
 end
 
 describe "String#delete_prefix!" do
   it "removes the found prefix" do
     s = 'hello'
-    s.delete_prefix!('hell').should equal(s)
+    s.delete_prefix!('hell').should.equal?(s)
     s.should == 'o'
   end
 
@@ -83,8 +76,8 @@ describe "String#delete_prefix!" do
   end
 
   it "raises a FrozenError when self is frozen" do
-    -> { 'hello'.freeze.delete_prefix!('hell') }.should raise_error(FrozenError)
-    -> { 'hello'.freeze.delete_prefix!('') }.should raise_error(FrozenError)
-    -> { ''.freeze.delete_prefix!('') }.should raise_error(FrozenError)
+    -> { 'hello'.freeze.delete_prefix!('hell') }.should.raise(FrozenError)
+    -> { 'hello'.freeze.delete_prefix!('') }.should.raise(FrozenError)
+    -> { ''.freeze.delete_prefix!('') }.should.raise(FrozenError)
   end
 end