test_weakref.rb: use single level WeakRef

* test/test_weakref.rb (make_weakref): return single level
  WeakRef, instead of multiple level, since the second level
  object may be still alive even after the final object get
  finalized, in test_recycled.

* test/test_weakref.rb (test_ref): move living object assertions
  from test_recycled.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44146 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/test_weakref.rb

@@ -4,21 +4,22 @@ require_relative './ruby/envutil'
 
 class TestWeakRef < Test::Unit::TestCase
   def make_weakref(level = 10)
-    obj = Object.new
-    str = obj.to_s
-    level.times {obj = WeakRef.new(obj)}
-    return WeakRef.new(obj), str
+    if level > 0
+      make_weakref(level - 1)
+    else
+      WeakRef.new(Object.new)
+    end
   end
 
   def test_ref
-    weak, str = make_weakref
-    assert_equal(str, weak.to_s)
+    obj = Object.new
+    weak = WeakRef.new(obj)
+    assert_equal(obj.to_s, weak.to_s)
+    assert_predicate(weak, :weakref_alive?)
   end
 
   def test_recycled
-    weak, str = make_weakref
-    assert_nothing_raised(WeakRef::RefError) {weak.to_s}
-    assert_predicate(weak, :weakref_alive?)
+    weak = make_weakref
     ObjectSpace.garbage_collect
     ObjectSpace.garbage_collect
     assert_raise(WeakRef::RefError) {weak.to_s}