diff --git a/test/etc/test_etc.rb b/test/etc/test_etc.rb
index f93c5a0e11..365c27021c 100644
--- a/test/etc/test_etc.rb
+++ b/test/etc/test_etc.rb
@@ -97,12 +97,12 @@ class TestEtc < Test::Unit::TestCase
   end
 
   def test_getgrnam
-    groups = {}
+    groups = Hash.new {[]}
     Etc.group do |s|
-      groups[s.name] ||= s.gid unless /\A\+/ =~ s.name
+      groups[s.name] |= [s.gid] unless /\A\+/ =~ s.name
     end
     groups.each_pair do |n, s|
-      assert_equal(s, Etc.getgrnam(n).gid)
+      assert_include(s, Etc.getgrnam(n).gid)
     end
   end