diff --git a/test/rubygems/test_gem_platform.rb b/test/rubygems/test_gem_platform.rb
index 0fb5bf59a5..831079acb2 100644
--- a/test/rubygems/test_gem_platform.rb
+++ b/test/rubygems/test_gem_platform.rb
@@ -144,6 +144,7 @@ class TestGemPlatform < Gem::TestCase
     test_cases.each do |arch, expected|
       platform = Gem::Platform.new arch
       assert_equal expected, platform.to_a, arch.inspect
+      assert_equal expected, Gem::Platform.new(platform.to_s).to_a, arch.inspect
     end
   end