diff --git a/ChangeLog b/ChangeLog
index c4d8f30ad4..8b833b6f86 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,7 @@
-Sat May  1 22:27:45 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Sat May  1 22:41:05 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/test/unit/assertions.rb (Test::Unit::Assertions#assert):
+	  keep the first trace.
 
 	* lib/test/unit/assertions.rb (Test::Unit::Assertions#assert):
 	  fixed filtering.  [ruby-core:29908]
diff --git a/lib/test/unit/assertions.rb b/lib/test/unit/assertions.rb
index a06962fceb..f4e4e74e1e 100644
--- a/lib/test/unit/assertions.rb
+++ b/lib/test/unit/assertions.rb
@@ -12,7 +12,7 @@ module Test
 
       def assert(test, msg = (nomsg = true; nil))
         unless nomsg or msg.instance_of?(String) or msg.instance_of?(Proc) or
-            (bt = caller).shift.rindex(MiniTest::MINI_DIR, 0)
+            (bt = caller).first.rindex(MiniTest::MINI_DIR, 0)
           bt.delete_if {|s| s.rindex(MiniTest::MINI_DIR, 0)}
           raise ArgumentError, "assertion message must be String or Proc, but #{msg.class} was given.", bt
         end