RefuteKindOf: also replace is_a? as well

config/default.yml

@@ -253,6 +253,7 @@ Minitest/RefuteKindOf:
   StyleGuide: 'https://github.com/rubocop/minitest-style-guide#refute-kind-of'
   Enabled: 'pending'
   VersionAdded: '0.10'
+  VersionChanged: '<<next>>'
 
 Minitest/RefuteMatch:
   Description: 'This cop enforces the test to use `refute_match` instead of using `refute(matcher.match(object))`.'

lib/rubocop/cop/minitest/refute_kind_of.rb

@@ -11,14 +11,19 @@ module Minitest
       #   refute(object.kind_of?(Class))
       #   refute(object.kind_of?(Class), 'message')
       #
+      #   # bad
+      #   # `is_a?` is an alias for `kind_of?`
+      #   refute(object.is_of?(Class))
+      #   refute(object.is_of?(Class), 'message')
+      #
       #   # good
       #   refute_kind_of(Class, object)
       #   refute_kind_of(Class, object, 'message')
       #
       class RefuteKindOf < Base
         extend MinitestCopRule
 
-        define_rule :refute, target_method: :kind_of?, inverse: true
+        define_rule :refute, target_method: %i[kind_of? is_a?], preferred_method: :refute_kind_of, inverse: true
       end
     end
   end

test/rubocop/cop/minitest/refute_kind_of_test.rb

@@ -22,6 +22,25 @@ def test_do_something
     RUBY
   end
 
+  def test_registers_offense_when_using_refute_with_kind_of
+    assert_offense(<<~RUBY)
+      class FooTest < Minitest::Test
+        def test_do_something
+          refute(object.is_a?(SomeClass))
+          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Prefer using `refute_kind_of(SomeClass, object)`.
+        end
+      end
+    RUBY
+
+    assert_correction(<<~RUBY)
+      class FooTest < Minitest::Test
+        def test_do_something
+          refute_kind_of(SomeClass, object)
+        end
+      end
+    RUBY
+  end
+
   def test_registers_offense_when_using_refute_with_kind_of_and_message
     assert_offense(<<~RUBY)
       class FooTest < Minitest::Test
@@ -41,6 +60,25 @@ def test_do_something
     RUBY
   end
 
+  def test_registers_offense_when_using_refute_with_kind_of_and_message
+    assert_offense(<<~RUBY)
+      class FooTest < Minitest::Test
+        def test_do_something
+          refute(object.is_a?(SomeClass), 'message')
+          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Prefer using `refute_kind_of(SomeClass, object, 'message')`.
+        end
+      end
+    RUBY
+
+    assert_correction(<<~RUBY)
+      class FooTest < Minitest::Test
+        def test_do_something
+          refute_kind_of(SomeClass, object, 'message')
+        end
+      end
+    RUBY
+  end
+
   def test_does_not_register_offense_when_using_refute_kind_of_method
     assert_no_offenses(<<~RUBY)
       class FooTest < Minitest::Test