add test for previous change to io.c.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@5149 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 10 insertions, 0 deletions

diff --git a/test/ruby/ut_eof.rb b/test/ruby/ut_eof.rb
index d1ad9a5fea..f1ce4f7198 100644
--- a/test/ruby/ut_eof.rb
+++ b/test/ruby/ut_eof.rb
@@ -16,6 +16,16 @@ module TestEOF
     }
   end
 
+  def test_eof_0_rw
+    return unless respond_to? :open_file_rw
+    open_file_rw("") {|f|
+      assert_equal("", f.read)
+      assert_equal(nil, f.read)
+      assert_equal(0, f.syswrite(""))
+      assert_equal(nil, f.read)
+    }
+  end
+
   def test_eof_1
     open_file("a") {|f|
       assert_equal("", f.read(0))