Add Worth the Drive fuel savings with road-routed estimates

Optional Fuel Savings feature (off by default): vehicle MPG in UK imperial gallons, fill amount in pounds or litres, persisted through the existing keychain/app-group store. Ranks the WHOLE station pool by estimated net saving (fuel-price saving at each pump minus the extra return-trip driving cost) using MapKit road distances with a straight-line fallback marked (est.).

The closest station with a valid price for the selected fuel is the comparison baseline and is labelled "Closest station"; other rows read "Save £X.XX after travel" / "£X.XX worse off after travel" / "Break even". Labels live in the shared model so they are unit-tested. The TOP badge still marks the cheapest pump price and reads "CHEAPEST" when the list is ranked by net saving.

Road routing now prioritises the Worth-the-Drive candidates plus the baseline and merges cache entries instead of replacing them, so far-out stations get real routes rather than permanent straight-line estimates. Numeric fields gain a Done button above the keypad (decimalPad has no Return key); the fill-up control is hidden unless the feature is configured; Favourites shares one session fill amount with the station list. 131 tests.
This commit is contained in:
FuelBoard Contributor
2026-10-11 14:34:53 +01:00
parent 1044d009ae
commit d7a0ecb79a
17 changed files with 1865 additions and 46 deletions
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../../../Shared/FuelSavings.swift
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import XCTest
#if SWIFT_PACKAGE
@testable import FuelBoardShared
#endif
/// Ranking rules for the Worth the Drive sort.
///
/// Regression: the sort used to rank only a shortlist of the nearest stations
/// whose ROAD ROUTES had been measured, and everything else was listed as
/// unavailable. Cheaper stations a few miles further out — the exact stations
/// the sort exists to surface — were dropped from the top of the list, and
/// stations on later pages showed no savings at all.
final class FuelSavingsEstimateTests: XCTestCase {
private let settings = FuelSavingsSettings(
enabled: true,
mpg: 45,
preferredAmount: FuelSavingsFillAmount(value: 40, unit: .pounds)
)
private let amount = FuelSavingsFillAmount(value: 40, unit: .pounds)
private func station(_ id: String,
price: Double?,
lat: Double = 51.5,
lng: Double = -0.1) -> FuelStation {
FuelStation(
id: id,
name: id,
brand: "X",
address: "",
postcode: "",
lat: lat,
lng: lng,
prices: price.map { [FuelType.e10: $0] } ?? [:],
priceUpdated: nil
)
}
/// Straight-line out-and-back estimate, as the app builds it when no road
/// route has been measured yet.
private func straightLine(_ miles: Double) -> FuelSavingsJourney {
FuelSavingsJourney(miles: miles, basis: .straightLine)
}
func testCheaperStationThreePointFiveMilesAwayIsRankedFirstWithASaving() {
// Nearest station: 1 mile away at 145.9p. The station the user can see
// in the Cheapest tab: 3.5 miles away at 138.9p.
let baseline = station("baseline", price: 145.9)
let candidate = station("cheaper-3.5", price: 138.9, lat: 51.55)
let filler = (0..<14).map { station("filler-\($0)", price: 150 + Double($0)) }
let pool = [baseline, candidate] + filler
let ranked = FuelSavingsEstimator.ranked(
pool,
fuel: .e10,
baseline: baseline,
settings: settings,
amount: amount,
journeyMiles: { s in
switch s.id {
case "baseline": return self.straightLine(2.0)
case "cheaper-3.5": return self.straightLine(7.0)
default: return self.straightLine(20.0)
}
}
)
XCTAssertEqual(ranked.count, pool.count)
XCTAssertEqual(ranked.first?.id, "cheaper-3.5",
"a cheaper station 3.5 miles away must rank above the nearest station")
let result = FuelSavingsEstimator.availability(
station: candidate,
fuel: .e10,
baseline: baseline,
settings: settings,
amount: amount,
journey: straightLine(7.0),
baselineJourney: straightLine(2.0)
)?.result
XCTAssertNotNil(result, "the station must show a saving, not an unavailable state")
XCTAssertGreaterThan(result?.netSavingGBP ?? -1, 0)
XCTAssertEqual(result?.status, .worthTheDrive)
XCTAssertEqual(result?.distanceBasis, .straightLine,
"unmeasured routes are reported as straight-line estimates")
}
func testEveryPricedStationInThePoolIsEstimatedNotJustAShortlist() {
// 40 stations, but only the first one has a measured road route — the
// old implementation capped the whole ranking to 12 shortlisted
// stations and returned "Outside route shortlist" for the rest.
let baseline = station("baseline", price: 145.9)
let pool = [baseline] + (0..<39).map { station("s\($0)", price: 135 + Double($0)) }
let ranked = FuelSavingsEstimator.ranked(
pool,
fuel: .e10,
baseline: baseline,
settings: settings,
amount: amount,
journeyMiles: { s in
s.id == "baseline"
? FuelSavingsJourney(miles: 2.0, basis: .roadRoute)
: self.straightLine(2.0 + (Double(s.id.dropFirst()) ?? 6))
}
)
XCTAssertEqual(ranked.count, pool.count)
for station in pool where station.id != "baseline" {
let availability = FuelSavingsEstimator.availability(
station: station,
fuel: .e10,
baseline: baseline,
settings: settings,
amount: amount,
journey: straightLine(10.0),
baselineJourney: FuelSavingsJourney(miles: 2.0, basis: .roadRoute)
)
XCTAssertNotNil(availability?.result,
"\(station.id) should carry an estimated saving, not an unavailable state")
}
}
func testMeasuredRoadRoutesAreReportedAsRoadRouteBasis() {
let baseline = station("baseline", price: 145.9)
let candidate = station("candidate", price: 138.9)
let result = FuelSavingsEstimator.availability(
station: candidate,
fuel: .e10,
baseline: baseline,
settings: settings,
amount: amount,
journey: FuelSavingsJourney(miles: 7.0, basis: .roadRoute),
baselineJourney: FuelSavingsJourney(miles: 2.0, basis: .roadRoute)
)?.result
XCTAssertEqual(result?.distanceBasis, .roadRoute)
XCTAssertFalse(FuelSavingsDistanceBasis.roadRoute.isEstimate)
}
func testMixedBasisIsReportedAsAnEstimate() {
let baseline = station("baseline", price: 145.9)
let candidate = station("candidate", price: 138.9)
// Baseline measured, candidate not: the comparison is only as good as
// its weakest leg, so it must be labelled an estimate.
let result = FuelSavingsEstimator.availability(
station: candidate,
fuel: .e10,
baseline: baseline,
settings: settings,
amount: amount,
journey: straightLine(7.0),
baselineJourney: FuelSavingsJourney(miles: 2.0, basis: .roadRoute)
)?.result
XCTAssertEqual(result?.distanceBasis, .straightLine)
}
func testStationWithoutAPriceIsUnavailable() {
let baseline = station("baseline", price: 145.9)
let noPrice = station("no-price", price: nil)
let availability = FuelSavingsEstimator.availability(
station: noPrice,
fuel: .e10,
baseline: baseline,
settings: settings,
amount: amount,
journey: straightLine(4.0),
baselineJourney: straightLine(2.0)
)
XCTAssertEqual(availability, .unavailable("No price"))
}
func testFeatureOffProducesNoSavingsRow() {
let baseline = station("baseline", price: 145.9)
let candidate = station("candidate", price: 138.9)
let availability = FuelSavingsEstimator.availability(
station: candidate,
fuel: .e10,
baseline: baseline,
settings: .defaults,
amount: amount,
journey: straightLine(4.0),
baselineJourney: straightLine(2.0)
)
XCTAssertNil(availability)
}
// MARK: - Required wording and baseline labelling
private var briefSettings: FuelSavingsSettings {
FuelSavingsSettings(enabled: true,
mpg: 30,
preferredAmount: FuelSavingsFillAmount(value: 60, unit: .pounds))
}
private var briefAmount: FuelSavingsFillAmount {
FuelSavingsFillAmount(value: 60, unit: .pounds)
}
/// The scenario from the brief: 30 MPG, £60 fill, baseline Rontec Shelf
/// (171.9p, 0.4 mi), candidate Shell Whetley Hill (167.9p, 3.8 mi).
///
/// Whetley Hill is 4p/litre cheaper, yet it is WORSE OFF — and that is
/// correct, not a calculation bug: £60 buys 34.90 L at 171.9p, so the
/// cheaper pump saves 34.90 × 4p = £1.40, while the extra 6.8 return miles
/// burn 6.8/30 × 4.54609 = 1.03 L at 167.9p = £1.73. Net ≈ −£0.33.
func testCheaperStationFurtherAwayIsWorseOffAfterTravel() {
let baseline = station("rontec-shelf", price: 171.9)
let candidate = station("shell-whetley-hill", price: 167.9)
let availability = FuelSavingsEstimator.availability(
station: candidate,
fuel: .e10,
baseline: baseline,
settings: briefSettings,
amount: briefAmount,
journey: straightLine(7.6), // 3.8 mi out and back
baselineJourney: straightLine(0.8) // 0.4 mi out and back
)
guard let result = availability?.result else {
return XCTFail("expected an estimate, got \(String(describing: availability))")
}
XCTAssertEqual(result.fillLitres, 34.904, accuracy: 0.005,
"the £60 budget buys litres at the BASELINE pump price")
XCTAssertEqual(result.grossSavingGBP, 1.396, accuracy: 0.005)
XCTAssertEqual(result.extraDistanceMiles, 6.8, accuracy: 0.001,
"only the return-trip DELTA counts — the shared journey is never counted twice")
XCTAssertEqual(result.extraDrivingCostGBP, 1.730, accuracy: 0.005)
XCTAssertEqual(result.netSavingGBP, -0.334, accuracy: 0.005)
XCTAssertEqual(result.status, .notWorthTheDrive)
XCTAssertEqual(result.headline(compact: true), "£0.33 worse off after travel (est.)")
}
func testMeasuredRoadRoutesDropTheEstimateMarker() {
let baseline = station("baseline", price: 171.9)
let candidate = station("candidate", price: 167.9)
let availability = FuelSavingsEstimator.availability(
station: candidate,
fuel: .e10,
baseline: baseline,
settings: briefSettings,
amount: briefAmount,
journey: FuelSavingsJourney(miles: 7.6, basis: .roadRoute),
baselineJourney: FuelSavingsJourney(miles: 0.8, basis: .roadRoute)
)
XCTAssertEqual(availability?.result?.distanceBasis, .roadRoute)
XCTAssertEqual(availability?.result?.headline(compact: true), "£0.33 worse off after travel")
XCTAssertEqual(availability?.result?.headline(), "£0.33 worse off after travel")
}
func testBaselineRowIsLabelledClosestStation() {
let baseline = station("nearest", price: 171.9)
let availability = FuelSavingsEstimator.availability(
station: baseline,
fuel: .e10,
baseline: baseline,
settings: briefSettings,
amount: briefAmount,
journey: straightLine(0.8),
baselineJourney: straightLine(0.8)
)
XCTAssertEqual(availability?.result?.status, .baseline)
XCTAssertEqual(availability?.result?.headline(compact: true), "Closest station")
XCTAssertEqual(FuelSavingsStatus.baseline.displayName, "Closest station")
XCTAssertEqual(availability?.result?.netSavingGBP, 0)
XCTAssertEqual(availability?.result?.extraDistanceMiles, 0)
}
func testPositiveResultHeadlineSaysSaveAfterTravel() {
// 4p cheaper AND almost the same distance, so the saving survives travel.
let baseline = station("baseline", price: 160.0)
let candidate = station("candidate", price: 150.0)
let availability = FuelSavingsEstimator.availability(
station: candidate,
fuel: .e10,
baseline: baseline,
settings: briefSettings,
amount: briefAmount,
journey: straightLine(6.4),
baselineJourney: straightLine(6.0)
)
guard let result = availability?.result else {
return XCTFail("expected an estimate, got \(String(describing: availability))")
}
XCTAssertEqual(result.status, .worthTheDrive)
// £60 buys 37.5 L at 160p; 10p/litre cheaper saves £3.75; 0.4 extra
// return miles cost ~£0.09. Net ≈ £3.66.
XCTAssertEqual(result.netSavingGBP, 3.659, accuracy: 0.005)
XCTAssertEqual(result.headline(compact: true), "Save £3.66 after travel (est.)")
}
func testNeutralResultHeadlineIsBreakEven() {
// 0.1p cheaper over the same distance: inside the break-even tolerance.
let baseline = station("baseline", price: 150.0)
let candidate = station("candidate", price: 149.9)
let availability = FuelSavingsEstimator.availability(
station: candidate,
fuel: .e10,
baseline: baseline,
settings: briefSettings,
amount: briefAmount,
journey: straightLine(6.0),
baselineJourney: straightLine(6.0)
)
XCTAssertEqual(availability?.result?.status, .breakEven)
XCTAssertEqual(availability?.result?.headline(compact: true), "Break even")
XCTAssertEqual(availability?.result?.headline(), "Break even")
}
/// The exact strings the brief asks for.
func testHeadlineWordingMatchesTheBrief() {
XCTAssertEqual(FuelSavingsResult.baselineHeadline, "Closest station")
XCTAssertEqual(FuelSavingsResult.breakEvenHeadline, "Break even")
let saving = FuelSavingsResult(fillLitres: 34.9,
grossSavingGBP: 1.40,
extraDrivingCostGBP: 0.88,
extraDistanceMiles: 3.5,
netSavingGBP: 0.52,
status: .worthTheDrive,
distanceBasis: .roadRoute)
XCTAssertEqual(saving.headline(), "Save £0.52 after travel")
let loss = FuelSavingsResult(fillLitres: 34.9,
grossSavingGBP: 1.40,
extraDrivingCostGBP: 1.71,
extraDistanceMiles: 6.8,
netSavingGBP: -0.31,
status: .notWorthTheDrive,
distanceBasis: .roadRoute)
XCTAssertEqual(loss.headline(), "£0.31 worse off after travel")
}
/// The sort must order by NET saving, not pump price: a pricier station can
/// win when the cheaper one is far enough away.
func testSortingRanksByNetSavingNotPumpPrice() {
let baseline = station("baseline", price: 171.9)
let cheapButFar = station("cheap-but-far", price: 167.9)
let pricierButNear = station("pricier-but-near", price: 169.9)
let ranked = FuelSavingsEstimator.ranked(
[baseline, cheapButFar, pricierButNear],
fuel: .e10,
baseline: baseline,
settings: briefSettings,
amount: briefAmount,
journeyMiles: { s in
switch s.id {
case "baseline": return self.straightLine(0.8)
case "cheap-but-far": return self.straightLine(7.6)
default: return self.straightLine(1.2)
}
}
)
XCTAssertEqual(ranked.first?.id, "pricier-but-near",
"net saving decides the order, not the pump price")
XCTAssertEqual(ranked.last?.id, "cheap-but-far")
}
}
@@ -0,0 +1,37 @@
import XCTest
#if SWIFT_PACKAGE
@testable import FuelBoardShared
#endif
final class FuelSavingsRoutingCacheTests: XCTestCase {
override func setUp() {
super.setUp()
FuelStore.saveRoadDistances(sourceLat: 0, sourceLng: 0, entries: [:])
}
private func station(_ id: String, _ lat: Double, _ lng: Double) -> FuelStation {
FuelStation(id: id, name: id, brand: "X", address: "", postcode: "", lat: lat, lng: lng, prices: [.e10: 140], priceUpdated: nil)
}
func testJourneyDistanceUsesSeparateOutAndBackRoadRoutes() {
let s = station("a", 51.5074, -0.1278)
FuelStore.saveRoadDistances(
sourceLat: 51.6,
sourceLng: -0.1,
entries: ["a": CachedRoadDistance(meters: 3_200, lat: 51.5074, lng: -0.1278, returnMeters: 3_700)]
)
XCTAssertEqual(FuelStore.roadJourneyMeters(for: s, userLat: 51.6, userLng: -0.1), 6_900)
}
func testLegacyOneWayCacheDoublesForJourneyDistance() {
let s = station("a", 51.5074, -0.1278)
FuelStore.saveRoadDistances(
sourceLat: 51.6,
sourceLng: -0.1,
entries: ["a": CachedRoadDistance(meters: 3_200, lat: 51.5074, lng: -0.1278)]
)
XCTAssertEqual(FuelStore.roadJourneyMeters(for: s, userLat: 51.6, userLng: -0.1), 6_400)
}
}
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import XCTest
#if SWIFT_PACKAGE
@testable import FuelBoardShared
#endif
final class FuelSavingsCalculatorTests: XCTestCase {
func testUKMPGConversionUsesImperialGallons() {
XCTAssertEqual(FuelSavingsCalculator.fuelUsedLitres(distanceMiles: 10, mpg: 45), 1.0102, accuracy: 0.0001)
}
func testPoundsBudgetConvertsToLitresUsingBaselinePrice() throws {
let amount = FuelSavingsFillAmount(value: 40, unit: .pounds)
let litres = try FuelSavingsCalculator.fillLitres(amount: amount, baselinePricePencePerLitre: 160)
XCTAssertEqual(litres, 25.0, accuracy: 0.0001)
}
func testLitresAmountPassesThrough() throws {
let amount = FuelSavingsFillAmount(value: 35, unit: .litres)
let litres = try FuelSavingsCalculator.fillLitres(amount: amount, baselinePricePencePerLitre: 160)
XCTAssertEqual(litres, 35, accuracy: 0.0001)
}
func testNetSavingSubtractsAdditionalDrivingFuelCost() throws {
let result = try FuelSavingsCalculator.calculate(
mpg: 45,
amount: FuelSavingsFillAmount(value: 40, unit: .pounds),
baselinePricePencePerLitre: 160,
candidatePricePencePerLitre: 150,
baselineJourneyMiles: 2,
candidateJourneyMiles: 8
)
XCTAssertEqual(result.fillLitres, 25, accuracy: 0.0001)
XCTAssertEqual(result.grossSavingGBP, 2.50, accuracy: 0.0001)
XCTAssertEqual(result.extraDistanceMiles, 6, accuracy: 0.0001)
XCTAssertEqual(result.extraDrivingCostGBP, 0.9092, accuracy: 0.0001)
XCTAssertEqual(result.netSavingGBP, 1.5908, accuracy: 0.0001)
XCTAssertEqual(result.status, .worthTheDrive)
}
func testNegativeAndBreakEvenOutcomes() throws {
let negative = try FuelSavingsCalculator.calculate(
mpg: 45,
amount: FuelSavingsFillAmount(value: 10, unit: .litres),
baselinePricePencePerLitre: 150,
candidatePricePencePerLitre: 149,
baselineJourneyMiles: 1,
candidateJourneyMiles: 20
)
XCTAssertEqual(negative.status, .notWorthTheDrive)
XCTAssertLessThan(negative.netSavingGBP, 0)
let even = try FuelSavingsCalculator.calculate(
mpg: 45,
amount: FuelSavingsFillAmount(value: 10, unit: .litres),
baselinePricePencePerLitre: 150,
candidatePricePencePerLitre: 150,
baselineJourneyMiles: 2,
candidateJourneyMiles: 2
)
XCTAssertEqual(even.status, .breakEven)
}
func testInvalidInputsRejected() {
XCTAssertThrowsError(try FuelSavingsCalculator.fillLitres(amount: FuelSavingsFillAmount(value: 40, unit: .pounds), baselinePricePencePerLitre: 0))
XCTAssertThrowsError(try FuelSavingsCalculator.calculate(mpg: 0, amount: FuelSavingsFillAmount(value: 40, unit: .pounds), baselinePricePencePerLitre: 160, candidatePricePencePerLitre: 150, baselineJourneyMiles: 1, candidateJourneyMiles: 2))
XCTAssertThrowsError(try FuelSavingsCalculator.calculate(mpg: 500, amount: FuelSavingsFillAmount(value: 40, unit: .pounds), baselinePricePencePerLitre: 160, candidatePricePencePerLitre: 150, baselineJourneyMiles: 1, candidateJourneyMiles: 2))
}
func testSwitchingPoundsToLitresPreservesPhysicalQuantity() throws {
let pounds = FuelSavingsFillAmount(value: 40, unit: .pounds)
let litres = try FuelSavingsCalculator.convert(amount: pounds, to: .litres, referencePricePencePerLitre: 160)
XCTAssertEqual(litres.unit, .litres)
XCTAssertEqual(litres.value, 25, accuracy: 0.0001)
let back = try FuelSavingsCalculator.convert(amount: litres, to: .pounds, referencePricePencePerLitre: 160)
XCTAssertEqual(back.value, 40, accuracy: 0.0001)
}
func testSortingPlacesUnavailableAfterSavingsAndBreaksTies() {
let a = FuelSavingsRankedStation(stationID: "a", result: .available(.init(fillLitres: 25, grossSavingGBP: 2, extraDrivingCostGBP: 1, extraDistanceMiles: 3, netSavingGBP: 1, status: .worthTheDrive)), distanceMiles: 5, pricePencePerLitre: 150)
let b = FuelSavingsRankedStation(stationID: "b", result: .available(.init(fillLitres: 25, grossSavingGBP: 3, extraDrivingCostGBP: 1, extraDistanceMiles: 2, netSavingGBP: 2, status: .worthTheDrive)), distanceMiles: 8, pricePencePerLitre: 149)
let c = FuelSavingsRankedStation(stationID: "c", result: .unavailable("No route"), distanceMiles: 1, pricePencePerLitre: 140)
XCTAssertEqual(FuelSavingsCalculator.sortedForWorthTheDrive([a, c, b]).map(\.stationID), ["b", "a", "c"])
}
}
final class FuelSavingsSettingsTests: XCTestCase {
func testSettingsValidationRequiresEnabledMPGAndFillAmount() {
XCTAssertFalse(FuelSavingsSettings(enabled: false, mpg: 45, preferredAmount: .init(value: 40, unit: .pounds)).isConfigured)
XCTAssertFalse(FuelSavingsSettings(enabled: true, mpg: 0, preferredAmount: .init(value: 40, unit: .pounds)).isConfigured)
XCTAssertFalse(FuelSavingsSettings(enabled: true, mpg: 45, preferredAmount: .init(value: 0, unit: .pounds)).isConfigured)
XCTAssertTrue(FuelSavingsSettings(enabled: true, mpg: 45, preferredAmount: .init(value: 40, unit: .pounds)).isConfigured)
}
}
@@ -0,0 +1,69 @@
import XCTest
@testable import FuelBoardShared
/// Shared payload storage must survive an install whose provisioning profile
/// has NO `com.apple.security.application-groups` entitlement (free/personal
/// team and SideStore installs) — the exact situation this test runner is in.
///
/// Regression guard: `appGroupFileURL` used to return nil without a group
/// container, so every save silently failed and every load returned empty. That
/// left `loadStations()` permanently empty (letting the freshness gate skip the
/// fetch for ever, i.e. a blank station list) and re-downloaded the ~2.8 MB
/// dump on every refresh. Storage now falls back to the app's own container.
final class FuelStoreFileCacheTests: XCTestCase {
func testSharedFileURLExistsWithoutAppGroupContainer() {
XCTAssertNotNil(
FuelStore.appGroupFileURL("fuelboard.test.probe.json"),
"storage must resolve to a writable location even when the App Group container is unprovisioned"
)
}
func testSharedFileRoundTripsWithoutAppGroupContainer() throws {
let name = "fuelboard.test.roundtrip.json"
let payload = Data("hello-cache".utf8)
XCTAssertTrue(
FuelStore.saveAppGroupFile(payload, name: name),
"save must succeed without an App Group container"
)
XCTAssertEqual(FuelStore.loadAppGroupFile(name), payload)
if let url = FuelStore.appGroupFileURL(name) {
try? FileManager.default.removeItem(at: url)
}
}
/// The dump cache is what stops a ~2.8 MB re-download on every refresh, so
/// it must round-trip too — not just the station list.
func testDumpCacheRoundTripsWithoutAppGroupContainer() {
let day = "2026-01-01"
let data = Data(repeating: 7, count: 4096)
MirrorFuelProvider.saveDumpCache(day: day, data: data)
let cache = MirrorFuelProvider.loadDumpCache()
XCTAssertEqual(cache?.day, day, "cached dump day must survive a round-trip")
XCTAssertEqual(cache?.data, data, "cached dump payload must survive a round-trip")
if let url = FuelStore.appGroupFileURL(MirrorFuelProvider.liveDumpCacheFileName) {
try? FileManager.default.removeItem(at: url)
}
}
/// The road-distance cache is memoized in memory because re-reading it per
/// station (it lives in the keychain) stalled the main thread past the iOS
/// launch watchdog. A save must therefore invalidate the memo — a stale
/// in-memory cache would show wrong distances after a route refresh.
func testRoadDistanceMemoRefreshesAfterSave() {
FuelStore.saveRoadDistances(sourceLat: 51.0, sourceLng: -1.0, entries: [:])
XCTAssertEqual(FuelStore.loadRoadDistances()?.sourceLat, 51.0)
FuelStore.saveRoadDistances(sourceLat: 52.0, sourceLng: -2.0, entries: [:])
XCTAssertEqual(
FuelStore.loadRoadDistances()?.sourceLat, 52.0,
"load must reflect the newest save, not a stale memoized cache"
)
}
}