@resource_handlers @resolver_coverage
Feature: Handler resolver edge-case coverage
  As a developer maintaining the handler resolution subsystem
  I want to exercise the uncovered error paths in resolve_handler
  So that every branch in resolver.py is tested

  Background:
    Given the handler cache is cleared

  # --- Lines 72-73: empty module_path or class_name after split ---

  Scenario: Reject handler reference with empty module path
    When I try to resolve handler ref ":SomeClass"
    Then a handler resolution error should be raised with message "both module path and class name are required"

  Scenario: Reject handler reference with empty class name
    When I try to resolve handler ref "some.module:"
    Then a handler resolution error should be raised with message "both module path and class name are required"

  # --- Lines 84-87: generic Exception (not ModuleNotFoundError) during import ---

  Scenario: Generic exception during module import raises HandlerResolutionError
    Given a module import that raises a generic RuntimeError
    When I try to resolve the rigged handler reference
    Then a handler resolution error should be raised with message "Error importing handler module"

  # --- Lines 99-102: Exception during handler class instantiation ---

  Scenario: Exception during handler instantiation raises HandlerResolutionError
    Given a module whose handler class raises TypeError on init
    When I try to resolve the rigged handler reference
    Then a handler resolution error should be raised with message "Cannot instantiate handler"

  # --- Lines 106-107: instantiated object does not satisfy ResourceHandler protocol ---

  Scenario: Handler class not satisfying ResourceHandler protocol is rejected
    Given a module whose handler class does not satisfy ResourceHandler
    When I try to resolve the rigged handler reference
    Then a handler resolution error should be raised with message "does not satisfy ResourceHandler protocol"

  # --- Whitespace-only reference triggers line 53-54 ---

  Scenario: Whitespace-only handler reference is treated as empty
    When I try to resolve handler ref "   "
    Then a handler resolution error should be raised with message "must not be empty"