chore(bench): exclude rides with low moving time ratio

3 files changed, 24 insertions, 7 deletions

diff --git a/cli/cli.go b/cli/cli.go
index cac29ec..37f64bb 100644
--- a/cli/cli.go
+++ b/cli/cli.go
@@ -32,7 +32,10 @@ var (
 	backtest    = flag.Bool("backtest", false, "run data benchmarks comparing computed values against stored reference values")
 )
 
-const backtestMinimumDistanceM = 10_000
+const (
+	backtestMinimumDistanceM   = 10_000
+	backtestMinimumMovingRatio = 0.8
+)
 
 func Run(db *sql.DB, configPath string, appConfig config.Config) {
 	switch {
@@ -134,12 +137,16 @@ func runBacktest(db *sql.DB) error {
 		fmt.Fprintf(table, "p%g\t%.1f\n", p, distribution[p])
 	}
 	table.Flush()
-	slog.Info("Moving time backtest", "rides", len(samples), "min_distance_m", backtestMinimumDistanceM, "mean_err_pct", math.Round(meanAbsErr(absErrors)*10)/10, "stderr_pct", math.Round(stdErrAbsErr(absErrors)*10)/10)
+	slog.Info("Moving time backtest", "rides", len(samples), "min_distance_m", backtestMinimumDistanceM, "min_moving_ratio", backtestMinimumMovingRatio, "mean_err_pct", math.Round(meanAbsErr(absErrors)*10)/10, "stderr_pct", math.Round(stdErrAbsErr(absErrors)*10)/10)
 	return nil
 }
 
 func isBacktestEligible(item rides.Ride) bool {
-	return item.GPXPath != "" && item.DistanceM >= backtestMinimumDistanceM && item.MovingTimeS > 0
+	return item.GPXPath != "" &&
+		item.DistanceM >= backtestMinimumDistanceM &&
+		item.MovingTimeS > 0 &&
+		item.ElapsedTimeS > 0 &&
+		float64(item.MovingTimeS)/float64(item.ElapsedTimeS) >= backtestMinimumMovingRatio
 }
 
 func meanAbsErr(absErrors []float64) float64 {
diff --git a/cli/cli_test.go b/cli/cli_test.go
index 6a3e148..59dec79 100644
--- a/cli/cli_test.go
+++ b/cli/cli_test.go
@@ -8,13 +8,23 @@ import (
 )
 
 func TestBacktestEligibilityExcludesShortDistances(t *testing.T) {
-	short := rides.Ride{GPXPath: "ride.gpx", DistanceM: 10_000 - 1, MovingTimeS: 1}
-	minimum := rides.Ride{GPXPath: "ride.gpx", DistanceM: 10_000, MovingTimeS: 1}
+	short := rides.Ride{GPXPath: "ride.gpx", DistanceM: 10_000 - 1, MovingTimeS: 8_000, ElapsedTimeS: 10_000}
+	minimum := rides.Ride{GPXPath: "ride.gpx", DistanceM: 10_000, MovingTimeS: 8_000, ElapsedTimeS: 10_000}
 
 	assert.False(t, isBacktestEligible(short))
 	assert.True(t, isBacktestEligible(minimum))
 }
 
+func TestBacktestEligibilityExcludesLowMovingRatio(t *testing.T) {
+	low := rides.Ride{GPXPath: "ride.gpx", DistanceM: 10_000, MovingTimeS: 7_999, ElapsedTimeS: 10_000}
+	boundary := rides.Ride{GPXPath: "ride.gpx", DistanceM: 10_000, MovingTimeS: 8_000, ElapsedTimeS: 10_000}
+	noElapsed := rides.Ride{GPXPath: "ride.gpx", DistanceM: 10_000, MovingTimeS: 1}
+
+	assert.False(t, isBacktestEligible(low))
+	assert.True(t, isBacktestEligible(boundary))
+	assert.False(t, isBacktestEligible(noElapsed))
+}
+
 func TestBacktestStatsUseUnroundedSamples(t *testing.T) {
 	absErrors := []float64{0, 0.1, 0.1}
 
diff --git a/ride/moving_time.go b/ride/moving_time.go
index 7d7f5fe..84cc28e 100644
--- a/ride/moving_time.go
+++ b/ride/moving_time.go
@@ -16,8 +16,8 @@ const movingTimeMinPowerW = 20
 // that can count as moving. Longer gaps are pauses (stops, lost signal).
 const movingTimeMaxGap = 120 * time.Second
 
-// Bench (117 rides, `-backtest`, distance >= 10 km):
-// absMean 0.6%, stderr 0.2, p50 0.2, p75 0.4, p90 1.2, p95 2.2, p99 4.8.
+// Bench (104 rides, `-backtest`, distance >= 10 km, moving/elapsed ratio >= 0.8):
+// absMean 0.4%, stderr 0.1, p50 0.2, p75 0.4, p90 0.8, p95 1.4, p99 2.9.
 func MovingTime(r Ride) time.Duration {
 	return movingTime(r, movingTimeMinSpeedMps, movingTimeMaxGap)
 }