-- TopDir-to-nothing chaining: ''
-- TopDir-to-global chaining: 'vGlobal'
-- TopDir no chaining required: 'vTopDir'
-- TopDir unset append chaining: 'aTopDir'
-- TopDir preset append chaining: 'vTopDir;aTopDir'
-- Subdir-to-parent chaining: 'vTopDir'
-- Subdir-to-global chaining: 'vGlobal'
-- Subdir no chaining required: 'vSubdir'
-- Subdir preset append chaining: 'vSubdir;aSubdir'
-- Subdir unset append chaining: 'aSubdir'
-- Subdir undefined append chaining: 'aSubdir'
-- Target-to-directory chaining: 'vTopDir'
-- Target unset append chaining: 'aTarget'
-- Target no chaining required: 'vTarget'
-- Target preset append chaining: 'vTarget;aTarget'
-- Target undefined get chaining: ''
-- Target undefined append chaining: 'aTarget'
-- Source-to-directory chaining: 'vTopDir'
-- Source unset append chaining: 'aSource'
-- Source no chaining required: 'vSource'
-- Source preset append chaining: 'vSource;aSource'
-- Source undefined get chaining: ''
-- Source undefined append chaining: 'aSource'
-- Test-to-directory chaining: 'vTopDir'
-- Test unset append chaining: 'aTest'
-- Test no chaining required: 'vTest'
-- Test preset append chaining: 'vTest;aTest'
-- Test undefined get chaining: ''
-- Test undefined append chaining: 'aTest'