* test/ruby/test_class.rb (test_module_function): tests for warnings.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@25145 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_class.rb

@@ -98,11 +98,38 @@ class TestClass < Test::Unit::TestCase
     assert_equal(nil, BasicObject.superclass)
   end
 
+  def verbose_warning
+    class << (stderr = "")
+      alias write <<
+    end
+    stderr, $stderr, verbose, $VERBOSE = $stderr, stderr, $VERBOSE, true
+    yield
+  ensure
+    stderr, $stderr, $VERBOSE = $stderr, stderr, verbose
+    return stderr
+  end
+
   def test_module_function
     c = Class.new
     assert_raise(TypeError) do
       Module.instance_method(:module_function).bind(c).call(:foo)
     end
+
+    stderr = verbose_warning do
+      Module.new do
+        def foo; end
+        def foo; end
+      end
+    end
+    assert_match(/method redefined; discarding old foo/, stderr)
+    stderr = verbose_warning do
+      Module.new do
+        def foo; end
+        alias bar foo
+        alias bar foo
+      end
+    end
+    assert_equal("", stderr)
   end
 
   def test_check_inheritable