1 files changed, 8 insertions, 2 deletions
diff --git a/test/ruby/test_env.rb b/test/ruby/test_env.rb
index b4c2d1f726..f6fcaace11 100644
--- a/test/ruby/test_env.rb
+++ b/test/ruby/test_env.rb
@@ -390,13 +390,19 @@ class TestEnv < Test::Unit::TestCase
 
   if /mswin|mingw/ =~ RUBY_PLATFORM
     def test_win32_blocksize
-      len = 32767 - ENV.to_a.flatten.inject(0) {|r,e| r + e.size + 2 }
+      keys = []
+      len = 32767 - ENV.to_a.flatten.inject(0) {|r,e| r + e.bytesize + 1}
       val = "bar" * 1000
       key = nil
+      while (len -= val.size + (key="foo#{len}").size + 2) > 0
+        keys << key
+        ENV[key] = val
+      end
       1.upto(12) {|i|
-        ENV[key] = val while (len -= val.size + (key="foo#{len}").size + 2) > 0
         assert_raise(Errno::EINVAL) { ENV[key] = val }
       }
+    ensure
+      keys.each {|k| ENV.delete(k)}
     end
   end
 end