Refine test of r55432

* test/stringio/test_stringio.rb (test_overflow): refine the
  conditinon, try to allocate strings until the buffer is located
  in higher half address.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55439 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 7 insertions, 1 deletions

diff --git a/test/stringio/test_stringio.rb b/test/stringio/test_stringio.rb
index ce84800d4b..5dd5de988a 100644
--- a/test/stringio/test_stringio.rb
+++ b/test/stringio/test_stringio.rb
@@ -686,7 +686,13 @@ class TestStringIO < Test::Unit::TestCase
     assert_separately(%w[-rstringio], "#{<<-"begin;"}\n#{<<-"end;"}")
     begin;
       limit = #{limit}
-      x = ("a"*0x100000)
+      ary = []
+      while true
+        x = "a"*0x100000
+        break if [x].pack("p").unpack("i!")[0] < 0
+        ary << x
+        skip if ary.size > 1000
+      end
       s = StringIO.new(x)
       s.gets("xxx", limit)
       assert_equal(0x100000, s.pos)