diff --git a/lib/rake/testtask.rb b/lib/rake/testtask.rb
index 6150f2f6e..56521d23d 100644
--- a/lib/rake/testtask.rb
+++ b/lib/rake/testtask.rb
@@ -181,7 +181,7 @@ def run_code # :nodoc:
       when :testrb
         "-S testrb"
       when :rake
-        "-r#{__dir__}/rake_test_loader"
+        "#{__dir__}/rake_test_loader.rb"
       end
     end
 
diff --git a/test/test_rake_test_task.rb b/test/test_rake_test_task.rb
index 8f7d13f84..fdb844607 100644
--- a/test/test_rake_test_task.rb
+++ b/test/test_rake_test_task.rb
@@ -128,7 +128,7 @@ def test_run_code_rake
       t.loader = :rake
     end
 
-    assert_match(/\A-r.*?\Z/, test_task.run_code)
+    assert_includes test_task.run_code, "lib/rake/rake_test_loader.rb"
   ensure
     Gem.loaded_specs["rake"] = rake
   end