dub test fails in subpackage's directory

[atilaneves]

System information

• dub version: 1.12.0
• OS Platform and distribution: Arch Linux
• compiler version dmd 2.083.0

Bug Description

dub test fails to compile for subpackage dependending on another subpackage in the subpackage directory.

How to reproduce?

# top-level dub.sdl
name "bug"

dependency ":foo" version="*"
dependency ":bar" version="*"

subPackage "foo"
subPackage "bar"

# foo/dub.sdl
name "foo"
dependency "bug:bar" path="../bar"

# bar/dub.sdl
name "bar"

dub test in the top-level directory works fine, but cd into foo and dub test fails with Sub package "bar:bar" doesn't exist.

Expected Behavior

It should be possible to test subpackages separately.