Setup and Teardown parameter changes type unexpectedly when run via NPM

## Summary

When running `nodeunit test/*-test.js` from the root of a project, the value of the parameter passed to `setUp()` and `tearDown()` is a function. When running the tests via `npm test` the type of the parameter is an object.
## nodeunit Version

0.6.4
## NPM Version

1.1.0-3
## Node.js Version

v0.6.9

Reproduce the issue by comparing `nodeunit test/*-test.js` with `npm test` using the reported Node.js and nodeunit versions. Trace how `setUp()` and `tearDown()` receive their parameters in each invocation, then add or update coverage so the parameter type is consistent when the behavior is corrected.

Written by the indexing model from the issue text.