Migrate cross-package ride test fixtures to the ridetest DSL

Replace raw FromColumns 4-array blocks in official_climb, mountain_pass
and web test rides with ridetest.MustRide strings. Add a Heading option to
ridetest for routes whose points are spaced differently per kilometer
(e.g. the mountain_pass expanded-bounds route at 0.1 degrees/km).

Lap, direction and cluster tests in official_climb keep FromColumns: the
DSL generates monotonic northeast coords and cannot express per-point
loops or reversals.

2 files changed, 42 insertions, 9 deletions

diff --git a/internal/ridetest/ride.go b/internal/ridetest/ride.go
index a6413a9..e74ce49 100644
--- a/internal/ridetest/ride.go
+++ b/internal/ridetest/ride.go
@@ -6,9 +6,10 @@
 //	ridetest.MustRide("2km at 7% | 1km at -7%")
 //
 // Options adjust the generated columns: Sampling (step in meters, default
-// 100), StartCoord (first point; later points progress northeast by 0.01° of
-// latitude and longitude per kilometer), StartTime (default the zero time,
-// one second between points) and StartElevation (default 0).
+// 100), StartCoord (first point; later points progress northeast at the
+// Heading rate, default 0.01° of latitude and longitude per kilometer),
+// StartTime (default the zero time, one second between points) and
+// StartElevation (default 0).
 package ridetest
 
 import (
@@ -46,6 +47,8 @@ type point struct {
 type options struct {
 	samplingM  float64
 	startCoord *geodist.Coord
+	headingLat float64
+	headingLon float64
 	startTime  time.Time
 	startElevM float64
 }
@@ -60,9 +63,28 @@ func Sampling(m float64) Option {
 }
 
 // StartCoord sets the coordinate of the first point. Each following point
-// progresses northeast by 0.01° of latitude and longitude per kilometer.
+// progresses northeast at the rate set by Heading, default 0.01° of latitude
+// and longitude per kilometer.
 func StartCoord(lat, lon float64) Option {
-	return func(o *options) { o.startCoord = &geodist.Coord{Lat: lat, Lon: lon} }
+	return func(o *options) {
+		o.startCoord = &geodist.Coord{Lat: lat, Lon: lon}
+		if o.headingLat == 0 {
+			o.headingLat = headingPerKm
+		}
+		if o.headingLon == 0 {
+			o.headingLon = headingPerKm
+		}
+	}
+}
+
+// Heading sets the latitude and longitude offset applied to each point per
+// kilometer of ride, in degrees (default 0.01 northeast when StartCoord is
+// set). Only meaningful together with StartCoord.
+func Heading(latPerKm, lonPerKm float64) Option {
+	return func(o *options) {
+		o.headingLat = latPerKm
+		o.headingLon = lonPerKm
+	}
 }
 
 // StartTime sets the timestamp of the first point; each following point is
@@ -80,7 +102,7 @@ func StartElevation(m float64) Option {
 //
 // Example: "2km at 7% | 1km at -7%".
 func Ride(dsl string, opts ...Option) (ride.Ride, error) {
-	o := options{samplingM: defaultSamplingM}
+	o := options{samplingM: defaultSamplingM, headingLat: headingPerKm, headingLon: headingPerKm}
 	for _, opt := range opts {
 		opt(&o)
 	}
@@ -250,10 +272,10 @@ func buildPoints(sections []section, o options) []point {
 		lat, lon = o.startCoord.Lat, o.startCoord.Lon
 	}
 	// Coordinates derive from the total distance so that exact multiples of
-	// the per-kilometer heading (0.01° x km as float64) stay exact; a running
-	// accumulation drifts after a few points.
+	// the per-kilometer heading stay exact; a running accumulation drifts
+	// after a few points.
 	coord := func(distanceM float64) geodist.Coord {
-		return geodist.Coord{Lat: lat + headingPerKm*(distanceM/1000), Lon: lon + headingPerKm*(distanceM/1000)}
+		return geodist.Coord{Lat: lat + o.headingLat*(distanceM/1000), Lon: lon + o.headingLon*(distanceM/1000)}
 	}
 	points := make([]point, 0, len(sections)+1)
 	elevation := o.startElevM
diff --git a/internal/ridetest/ride_test.go b/internal/ridetest/ride_test.go
index 69c084d..65483f2 100644
--- a/internal/ridetest/ride_test.go
+++ b/internal/ridetest/ride_test.go
@@ -53,6 +53,17 @@ func TestRideStartCoordHeading(t *testing.T) {
 	assert.InDelta(t, 5.12, r.Coords()[2].Lon, 1e-9)
 }
 
+func TestRideHeadingOption(t *testing.T) {
+	r, err := Ride("1km at 0%", StartCoord(43.0, 5.0), Heading(0.1, 0.1), Sampling(1000))
+	require.NoError(t, err)
+
+	// A single kilometer at 0.1°/km ends at (43.1, 5.1), matching rides whose
+	// points are spaced 0.1° apart over a kilometer.
+	require.Len(t, r.Coords(), 2)
+	assert.InDelta(t, 43.1, r.Coords()[1].Lat, 1e-9)
+	assert.InDelta(t, 5.1, r.Coords()[1].Lon, 1e-9)
+}
+
 func TestRideStartTime(t *testing.T) {
 	start := time.Date(2026, 8, 1, 10, 0, 0, 0, time.UTC)
 	r, err := Ride("1km at 0%", StartTime(start), Sampling(500))