Feature: ChunkedFileTraverser _read_file and add_command traversal coverage
  Direct coverage for diff lines that the parallel test runner may not
  reach via the acms_context_add.feature scenarios:
    acms/index.py  lines 597-612  (_read_file stat + size-check + read_text)
    context.py     lines 111-112  (add_command traverser invocation)

  Background:
    Given a temp file exists for read file coverage

  Scenario: _read_file returns AcmsIndexEntry for a normal readable file
    When I directly call _read_file with default traverser
    Then the direct read file result should be an AcmsIndexEntry

  Scenario: _read_file returns None when file exceeds max_file_size
    When I directly call _read_file with max_file_size 1
    Then the direct read file result should be None

  Scenario: add_command invokes the real traverser for an existing path
    When I call add_command with the real traverser and a mocked container
    Then the mocked add_to_context should have been called