"read" denied when Sandbox Security is enabled

Running TestBox on a suite of MXUnit-based unit tests works fine when Sandbox Security is disabled, but enabling it throws a read permission error with an unusual path:

"Error","ajp-nio-127.0.0.1-8020-exec-3","10/07/24","14:02:48","TestBox Development Suite B5A32C7D17AD6EBDB8AC5390F3091B7D84F04A3E8D0C80F475135275F1DDE63E","access denied ("java.io.FilePermission" "<site-root>\www\testbox\test-runner\<site-root>\www\tests\results\coverageReport" "read") The specific sequence of files included or processed is: <site-root>\www\testbox\test-runner\index.cfm, line: 162"

The path cited is a concatenation of two paths, which individually exist on disk:

  • \www\testbox\test-runner\
  • \www\tests\results\coverageReport

I’m using the Test Runner inside the web root at /www/testbox/test-runner/, and its Report Path value is the default <site-root>\www\tests\results.

Granting read access to this non-existant path via Sandbox Security allows testing to complete, but does anyone understand what I’m doing wrong for this exception to be thrown in the first place?

Thanks in advance.