Summary

config test
  schema validation error -> exit 5
  other execution error -> exit 2

• Return the documented validation-failed code for schema errors.
• Add Rust mapping tests and a portable regression case using the Microsoft.DSC.Debug/Echo resource with an unexpected property.
• Fixes Exit code 5 is documented for schema validation failures but never returned (schema errors exit with 2) #1736.

Evidence

• Before: Exit code 5 is documented for schema validation failures but never returned (schema errors exit with 2) #1736 reports that dsc config test returns 2 for an unknown resource property. config_test maps every invoke_test error to EXIT_DSC_ERROR; schema validation errors arrive as DscError::Schema.
• After: config_test maps DscError::Schema to the existing EXIT_VALIDATION_FAILED value (5), while other errors retain code 2. The regression test asserts exit code 5 and the unexpected-property diagnostic for outpt on Echo.
• Linux ARM64, PowerShell 7.6.7 / Pester 6.2.0: targeted Schema validation failures return exit code 5 test passed (1 passed, 0 failed).
• git diff --check: passed. Patch policy accepted 2 files with no binary changes.

Merge Danger

Door: two-way

Blast Radius: narrow

Only the exit status for schema errors returned by dsc config test changes; other errors keep their current code.