diff --git a/test/rubygems/test_gem_platform.rb b/test/rubygems/test_gem_platform.rb
index ddac59a8e0..a837f16e48 100644
--- a/test/rubygems/test_gem_platform.rb
+++ b/test/rubygems/test_gem_platform.rb
@@ -27,7 +27,7 @@ class TestGemPlatform < Gem::TestCase
   end
 
   def test_self_match_spec?
-    make_spec = ->platform do
+    make_spec = ->(platform) do
       util_spec "mygem-for-platform-match_spec", "1" do |s|
         s.platform = platform
       end
@@ -40,7 +40,7 @@ class TestGemPlatform < Gem::TestCase
   end
 
   def test_self_match_spec_with_match_gem_override
-    make_spec = ->name, platform do
+    make_spec = ->(name, platform) do
       util_spec name, "1" do |s|
         s.platform = platform
       end