[Boost-build] error: unknown feature "<preserve-test-targets>"

Subject: [Boost-build] error: unknown feature "<preserve-test-targets>"
From: Min Wang (qiaorang_at_[hidden])
Date: 2009-01-24 10:04:57

Is the right way to use <preserve-test-targets>:
...
local rule run-test ( test-name : sources + : requirements * )
{
    *requirements += <preserve-test-targets>on ;*

    import testing ;
    testing.make-test run-pyd
        : $(sources)
        : $(requirements)
        : $(test-name) ;
}

I got *error: unknown feature "<preserve-test-targets>" *when running it.

My enviroment is:
OS: Ubuntu 8.10
BOOST-BUILD Version: 2.0-m12-2
BJAM Version: 3.1.16-1

Thanks in advance.