The report

BacktestReport is what the standalone backtest binary prints, what --json emits, and what a sweep ranks on. crates/vike-analytics/src/report.rs's header defines it by what it does not do: the module does no metric math of its own — every number is a direct pass-through from the result or a single metrics:: call, so a divergence here is a wiring bug, not a math bug. The matches_direct_metrics_calls test holds that, asserting field-for-field equality against calling metrics:: directly on the same inputs.

Why it lives outside the harness

The header calls the module feature-free by design. The backtest harness sits behind vike-backtest's hist-replay feature, which pulls the optional data layer; the report needs nothing but serde and the metrics, so it lives in the vike-model-only crate instead, and the DataFusion-free leaf crates build the same summary rather than re-assembling their own. vike-report's LiveTearsheet composes this struct for the fields the two share, so a live tearsheet and a backtest tearsheet cannot drift apart. The harness's own report module re-exports everything and adds only the one piece that needs the gated profile parser — periods_per_year, below.

Deliberately compact

The struct doc is explicit that this is not an everything-drawer: it is the backtest binary's human table and --json schema and the sweep's ranking source. A caller that wants the long-form catalog — Sortino, Calmar, CAGR, SQN, VaR — composes this for the shared fields and adds its own from metrics::; LiveTearsheet is named as the worked example.

The human table

Display prints a fixed row set. The field docs are careful about which rows exist, because the table's shape predates two of the fields and stays byte-identical for a run that does not use them. The rows below are the module's own test fixture — a 1000 → 1010 → 990 → 1005 curve with one winning and one losing trade — with the Sharpe row left as its label, since that value depends on the annualization factor passed in:

name:          demo
final_equity:  1005.00
total_return:  0.5000%
n_trades:      2
win_rate:      50.0000%
sharpe:        <annualized Sharpe>
max_drawdown:  1.9802%
per_symbol_pnl:
  BTCUSDT: 5.00

• profit_factor is not printed. Its doc says the human table's row set predates the field; it exists for ranking objectives and JSON consumers.
• funding_paid prints only when nonzero, so a spot backtest's table is unchanged; it is always present in --json.
• A zero-trade run prints its diagnosis instead of the table. When zero_trade is Some, Display writes final_equity, n_trades: 0 and then the ranked causes from the zero-trade analyzer in place of the all-zero metric rows. For any run with trades the field is None, skipped on serialization and absent from the table.

The JSON contract for the sentinel

profit_factor carries the house sentinel: f64::INFINITY when there are no losing trades but some profit, 0.0 when there is neither. In --json it is serialized as null when non-finite, so a consumer sees an explicit "no meaningful ratio" rather than a number.

Annualization: derived from the interval, not matched against a string

BacktestReport::from_result(name, result, periods_per_year) takes the factor metrics::sharpe needs, because the result itself does not carry it. Two constants live beside the struct: DAILY_PERIODS_PER_YEAR = 252.0, the 252-trading-day equity convention for 1d bars, and DEFAULT_PERIODS_PER_YEAR = 252.0, the fallback for tick runs, kept equal so the Sharpe scale is at least consistent.

The caller — the backtest binary — picks the factor through crates/vike-backtest/src/harness/report.rs's periods_per_year(&BacktestProfile), the single source of truth so the single-run binary and the sweep rank the same profile on the same Sharpe scale. Its doc records why it is derived: Sharpe annualizes by sqrt(periods_per_year), where the count must be the number of return observations a year produces — one per bar. It used to return 252 for every interval, so a one-minute run was annualized as though its bars were daily, understating every intraday Sharpe by sqrt(1440) ≈ 37.9× — silently, because the number still looked like a Sharpe — and making --rank-by sharpe incoherent across a sweep whose points differ in interval.

Reading one

The read a backtest report guide walks a real table; runs on disk covers what else a run leaves behind. The tearsheet binary is the live equivalent — it renders the journal, not a backtest, from the same catalog with a wider field set.