Mocha test swallowing errors in the test code

I'm using the following to run my unit tests with Mocha:

NODE_ENV=test NODE_CONFIG_DIR=../config mocha --require babel-core/register --recursive

When I do this, I get a completely useless error of 'Exit status 1' if it fails to run the tests (for example, if I screwed up the location of an import on one of my tests).

How can I get it to spit out runtime errors and line numbers when it runs the tests like I get when I run the code?