Test driver package practicalmeteor:mocha missing `runTests` export

I've just updated to meteor 1.3 and have been trying to use mocha for testing. I haven't used it before, so I'm not sure if I'm implementing it wrong, but I get the error

Test driver package practicalmeteor:mocha missing `runTests` export

in the chrome debug window when I run my app with

meteor test --driver-package practicalmeteor:mocha

I don't think the issue is with my tests, since the crash is happening as the app is starting. I do get the confirmation in the cmd that my app is running

=> App running at: http://localhost:3000/