{
  "formula": "billable_seconds * hourly_rate / 3600",
  "cases": {
    "whole-hour": {"billable_seconds": 3600, "expected_amount": 2500},
    "fraction-nearest": {"billable_seconds": 3599, "expected_amount": 2000},
    "excluded-half-hour": {"billable_seconds": 1800, "expected_amount": 1500},
    "one-second-up": {"billable_seconds": 1, "expected_amount": 28},
    "excluded-ten-minutes": {"billable_seconds": 6600, "expected_amount": 3300}
  }
}