Notify does not notifies on :failure with boot-test

It looks like, by looking at the code, a failure is only considered when an exception is thrown and indeed [boot-test](https://github.com/adzerk-oss/boot-test/blob/master/src/adzerk/boot_test.clj#L152) throws.

However I cannot hear the failure sound playing.

EDIT: I am on `2.6.0`, trying on `2.7.0-rc1`

Start by reproducing the failure notification with boot-test, using the linked source at src/adzerk/boot_test.clj around line 152 and the reported Boot versions 2.6.0 and 2.7.0-rc1. Trace how the thrown exception reaches the :failure notification and verify that the failure sound plays when the issue is fixed.

Written by the indexing model from the issue text.