{
  "fixtures": [
    {
      "name": "required_before_informational",
      "description": "Required validations must be processed before informational ones",
      "input": {
        "validations": [
          {"id": "val-001", "level": "required", "name": "schema_check"},
          {"id": "val-002", "level": "informational", "name": "style_lint"},
          {"id": "val-003", "level": "required", "name": "type_check"},
          {"id": "val-004", "level": "informational", "name": "doc_coverage"}
        ],
        "expected_order": ["val-001", "val-003", "val-002", "val-004"]
      },
      "expected_error": null
    },
    {
      "name": "all_informational_ordering_preserved",
      "description": "When all validations are informational, original order is preserved",
      "input": {
        "validations": [
          {"id": "val-010", "level": "informational", "name": "lint_a"},
          {"id": "val-011", "level": "informational", "name": "lint_b"},
          {"id": "val-012", "level": "informational", "name": "lint_c"}
        ],
        "expected_order": ["val-010", "val-011", "val-012"]
      },
      "expected_error": null
    },
    {
      "name": "duplicate_attachment_ids_rejected",
      "description": "Two validations with the same attachment ID cause a conflict error",
      "input": {
        "validations": [
          {"id": "val-020", "level": "required", "name": "check_a", "attachment_id": "att-1"},
          {"id": "val-021", "level": "required", "name": "check_b", "attachment_id": "att-1"}
        ]
      },
      "expected_error": "duplicate attachment ID: att-1 (used by val-020 and val-021)"
    },
    {
      "name": "duplicate_attachment_ids_across_levels",
      "description": "Duplicate attachment ID across required and informational levels",
      "input": {
        "validations": [
          {"id": "val-030", "level": "required", "name": "schema_check", "attachment_id": "att-shared"},
          {"id": "val-031", "level": "informational", "name": "lint_check", "attachment_id": "att-shared"}
        ]
      },
      "expected_error": "duplicate attachment ID: att-shared (used by val-030 and val-031)"
    },
    {
      "name": "empty_validations_list",
      "description": "An empty list of validations is accepted without error",
      "input": {
        "validations": [],
        "expected_order": []
      },
      "expected_error": null
    },
    {
      "name": "unknown_validation_level",
      "description": "Validation with unrecognized level is rejected",
      "input": {
        "validations": [
          {"id": "val-040", "level": "critical", "name": "severity_check"}
        ]
      },
      "expected_error": "unknown validation level: critical (expected: required, informational)"
    }
  ]
}