[ruby-core:21605] Couple questions about testing Ruby interpreters

I am trying to apply Brent's MBARI patches to Ruby 1.8.7 p72 to Ruby 1.8.6
p287. I am fairly sure I am doing some things the hard way and I would like
to find a better way.

1) When I compile a new version of Ruby I want to run test/runner.rb to
check all the tests. If I use the command ./ruby test/runner.rb I will use
the local directories Ruby executable but I am using the systems lib files.
This is a problem if say the system had 1.8.6 installed and I am trying to
test 1.8.7. I am assuming there is a way to run the local Ruby executable
and the local libs without installing the libs in the system, but I can't
seem to find it.

2) I ran test/runner.rb for Ruby 1.8.6 p287 patched with MBARI patches 1 and
2 and there were no errors or failures. If I run test/yaml/test_yaml.rb I
get 1 error:
  1) Error:
test_object_id_collision(YAML_Unit_Tests):
RuntimeError: id collision in ordered map
    test/yaml/test_yaml.rb:1281:in `test_object_id_collision'
Why is this test erroring when only test/yaml/test_yaml.rb is executed but
not when test/runner.rb executes the same test?

3) When trying to measure memory usage of the Ruby interpreter, it would
appear that GNU time would be able to measure the maximum memory usage.
Either I am using it wrong or GNU time is broken as I keep getting 0Kb
memory used. Short of watching top manually or writing a script to
constantly poll memory is there a way to get the maximum memory used? If I
do need a script to measure memory has someone else already written one so
that I don't have to reinvent the wheel?

- Michael