FuelBoard Contributor
d0a89d97d5
Calculation audit (brief config: 30 MPG imperial, £60 fill-up, baseline
Rontec Shelf 171.9p at 0.4 mi):
- One mile<->kilometre constant pair (kilometresPerMile 1.609344,
metresPerMile 1609.344) replaces the mixed 1609.34 / 0.621371 / 1.60934
used in the savings path. Effect ~2 ppm (invisible), but the conversions
are now auditable in one place.
- New FuelSavingsCalculationAuditTests (20 deterministic tests, no live
MKDirections) pins the brief's three stations - Tesco 170.9p/2.0 mi,
MFG Hare & Hounds 172.9p/2.8 mi, PGG Napoleon 171.9p/2.8 mi - plus
imperial-vs-US gallon, MPG and budget scaling, the break-even tolerance
boundary, the nearer-candidate clamp, route-unavailable, mixed-basis
estimates and display-rounding boundaries.
- Formula unchanged, and verified correct: fixed quantity (budget / baseline
price), pump saving, round-trip extra distance clamped at zero, travel fuel
priced at the candidate station, +/-5p break even, baseline labelled
"Closest station", sorting on the unrounded net saving. The brief's "£0.18"
for Tesco is the rounded 1 dp extra-distance caption (2.02-2.05 mi reads as
"2.0 mi"), not a rounding bug in the money.
UI (uncommitted since d7a0ecb):
- Done bar drawn in the bottom safe area from keyboard notifications:
.toolbar(placement: .keyboard) is device-dependent (present on the 15 Pro,
absent on the SE on the same iOS build).
- Favourite star in the More-info heading, wired to the same fuel-scoped
toggle as the listing rows at all three call sites.
- CHEAPEST/TOP badge moved above the price so it reads as part of it.
- Listing rows carry the real session fill-up amount instead of a hard zero
(the compact banner does not print it today; a future row layout would).
153 tests, 0 failures. Simulator and device builds succeed.
436 lines
18 KiB
Swift
436 lines
18 KiB
Swift
import XCTest
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#if SWIFT_PACKAGE
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@testable import FuelBoardShared
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#endif
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/// Ranking rules for the Worth the Drive sort.
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///
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/// Regression: the sort used to rank only a shortlist of the nearest stations
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/// whose ROAD ROUTES had been measured, and everything else was listed as
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/// unavailable. Cheaper stations a few miles further out — the exact stations
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/// the sort exists to surface — were dropped from the top of the list, and
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/// stations on later pages showed no savings at all.
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final class FuelSavingsEstimateTests: XCTestCase {
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private let settings = FuelSavingsSettings(
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enabled: true,
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mpg: 45,
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preferredAmount: FuelSavingsFillAmount(value: 40, unit: .pounds)
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)
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private let amount = FuelSavingsFillAmount(value: 40, unit: .pounds)
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private func station(_ id: String,
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price: Double?,
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lat: Double = 51.5,
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lng: Double = -0.1) -> FuelStation {
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FuelStation(
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id: id,
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name: id,
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brand: "X",
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address: "",
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postcode: "",
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lat: lat,
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lng: lng,
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prices: price.map { [FuelType.e10: $0] } ?? [:],
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priceUpdated: nil
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)
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}
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/// Straight-line out-and-back estimate, as the app builds it when no road
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/// route has been measured yet.
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private func straightLine(_ miles: Double) -> FuelSavingsJourney {
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FuelSavingsJourney(miles: miles, basis: .straightLine)
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}
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func testCheaperStationThreePointFiveMilesAwayIsRankedFirstWithASaving() {
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// Nearest station: 1 mile away at 145.9p. The station the user can see
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// in the Cheapest tab: 3.5 miles away at 138.9p.
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let baseline = station("baseline", price: 145.9)
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let candidate = station("cheaper-3.5", price: 138.9, lat: 51.55)
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let filler = (0..<14).map { station("filler-\($0)", price: 150 + Double($0)) }
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let pool = [baseline, candidate] + filler
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let ranked = FuelSavingsEstimator.ranked(
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pool,
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fuel: .e10,
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baseline: baseline,
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settings: settings,
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amount: amount,
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journeyMiles: { s in
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switch s.id {
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case "baseline": return self.straightLine(2.0)
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case "cheaper-3.5": return self.straightLine(7.0)
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default: return self.straightLine(20.0)
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}
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}
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)
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XCTAssertEqual(ranked.count, pool.count)
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XCTAssertEqual(ranked.first?.id, "cheaper-3.5",
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"a cheaper station 3.5 miles away must rank above the nearest station")
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let result = FuelSavingsEstimator.availability(
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station: candidate,
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fuel: .e10,
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baseline: baseline,
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settings: settings,
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amount: amount,
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journey: straightLine(7.0),
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baselineJourney: straightLine(2.0)
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)?.result
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XCTAssertNotNil(result, "the station must show a saving, not an unavailable state")
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XCTAssertGreaterThan(result?.netSavingGBP ?? -1, 0)
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XCTAssertEqual(result?.status, .worthTheDrive)
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XCTAssertEqual(result?.distanceBasis, .straightLine,
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"unmeasured routes are reported as straight-line estimates")
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}
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func testEveryPricedStationInThePoolIsEstimatedNotJustAShortlist() {
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// 40 stations, but only the first one has a measured road route — the
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// old implementation capped the whole ranking to 12 shortlisted
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// stations and returned "Outside route shortlist" for the rest.
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let baseline = station("baseline", price: 145.9)
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let pool = [baseline] + (0..<39).map { station("s\($0)", price: 135 + Double($0)) }
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let ranked = FuelSavingsEstimator.ranked(
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pool,
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fuel: .e10,
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baseline: baseline,
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settings: settings,
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amount: amount,
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journeyMiles: { s in
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s.id == "baseline"
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? FuelSavingsJourney(miles: 2.0, basis: .roadRoute)
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: self.straightLine(2.0 + (Double(s.id.dropFirst()) ?? 6))
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}
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)
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XCTAssertEqual(ranked.count, pool.count)
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for station in pool where station.id != "baseline" {
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let availability = FuelSavingsEstimator.availability(
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station: station,
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fuel: .e10,
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baseline: baseline,
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settings: settings,
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amount: amount,
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journey: straightLine(10.0),
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baselineJourney: FuelSavingsJourney(miles: 2.0, basis: .roadRoute)
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)
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XCTAssertNotNil(availability?.result,
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"\(station.id) should carry an estimated saving, not an unavailable state")
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}
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}
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func testMeasuredRoadRoutesAreReportedAsRoadRouteBasis() {
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let baseline = station("baseline", price: 145.9)
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let candidate = station("candidate", price: 138.9)
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let result = FuelSavingsEstimator.availability(
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station: candidate,
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fuel: .e10,
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baseline: baseline,
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settings: settings,
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amount: amount,
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journey: FuelSavingsJourney(miles: 7.0, basis: .roadRoute),
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baselineJourney: FuelSavingsJourney(miles: 2.0, basis: .roadRoute)
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)?.result
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XCTAssertEqual(result?.distanceBasis, .roadRoute)
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XCTAssertFalse(FuelSavingsDistanceBasis.roadRoute.isEstimate)
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}
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func testMixedBasisIsReportedAsAnEstimate() {
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let baseline = station("baseline", price: 145.9)
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let candidate = station("candidate", price: 138.9)
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// Baseline measured, candidate not: the comparison is only as good as
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// its weakest leg, so it must be labelled an estimate.
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let result = FuelSavingsEstimator.availability(
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station: candidate,
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fuel: .e10,
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baseline: baseline,
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settings: settings,
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amount: amount,
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journey: straightLine(7.0),
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baselineJourney: FuelSavingsJourney(miles: 2.0, basis: .roadRoute)
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)?.result
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XCTAssertEqual(result?.distanceBasis, .straightLine)
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}
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func testStationWithoutAPriceIsUnavailable() {
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let baseline = station("baseline", price: 145.9)
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let noPrice = station("no-price", price: nil)
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let availability = FuelSavingsEstimator.availability(
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station: noPrice,
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fuel: .e10,
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baseline: baseline,
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settings: settings,
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amount: amount,
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journey: straightLine(4.0),
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baselineJourney: straightLine(2.0)
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)
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XCTAssertEqual(availability, .unavailable("No price"))
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}
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func testFeatureOffProducesNoSavingsRow() {
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let baseline = station("baseline", price: 145.9)
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let candidate = station("candidate", price: 138.9)
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let availability = FuelSavingsEstimator.availability(
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station: candidate,
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fuel: .e10,
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baseline: baseline,
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settings: .defaults,
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amount: amount,
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journey: straightLine(4.0),
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baselineJourney: straightLine(2.0)
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)
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XCTAssertNil(availability)
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}
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// MARK: - Required wording and baseline labelling
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private var briefSettings: FuelSavingsSettings {
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FuelSavingsSettings(enabled: true,
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mpg: 30,
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preferredAmount: FuelSavingsFillAmount(value: 60, unit: .pounds))
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}
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private var briefAmount: FuelSavingsFillAmount {
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FuelSavingsFillAmount(value: 60, unit: .pounds)
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}
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/// The scenario from the brief: 30 MPG, £60 fill, baseline Rontec Shelf
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/// (171.9p, 0.4 mi), candidate Shell Whetley Hill (167.9p, 3.8 mi).
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///
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/// Whetley Hill is 4p/litre cheaper, yet it is WORSE OFF — and that is
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/// correct, not a calculation bug: £60 buys 34.90 L at 171.9p, so the
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/// cheaper pump saves 34.90 × 4p = £1.40, while the extra 6.8 return miles
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/// burn 6.8/30 × 4.54609 = 1.03 L at 167.9p = £1.73. Net ≈ −£0.33.
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func testCheaperStationFurtherAwayIsWorseOffAfterTravel() {
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let baseline = station("rontec-shelf", price: 171.9)
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let candidate = station("shell-whetley-hill", price: 167.9)
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let availability = FuelSavingsEstimator.availability(
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station: candidate,
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fuel: .e10,
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baseline: baseline,
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settings: briefSettings,
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amount: briefAmount,
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journey: straightLine(7.6), // 3.8 mi out and back
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baselineJourney: straightLine(0.8) // 0.4 mi out and back
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)
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guard let result = availability?.result else {
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return XCTFail("expected an estimate, got \(String(describing: availability))")
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}
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XCTAssertEqual(result.fillLitres, 34.904, accuracy: 0.005,
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"the £60 budget buys litres at the BASELINE pump price")
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XCTAssertEqual(result.grossSavingGBP, 1.396, accuracy: 0.005)
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XCTAssertEqual(result.extraDistanceMiles, 6.8, accuracy: 0.001,
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"only the return-trip DELTA counts — the shared journey is never counted twice")
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XCTAssertEqual(result.extraDrivingCostGBP, 1.730, accuracy: 0.005)
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XCTAssertEqual(result.netSavingGBP, -0.334, accuracy: 0.005)
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XCTAssertEqual(result.status, .notWorthTheDrive)
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XCTAssertEqual(result.headline(compact: true), "£0.33 worse off after travel (est.)")
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}
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func testMeasuredRoadRoutesDropTheEstimateMarker() {
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let baseline = station("baseline", price: 171.9)
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let candidate = station("candidate", price: 167.9)
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let availability = FuelSavingsEstimator.availability(
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station: candidate,
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fuel: .e10,
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baseline: baseline,
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settings: briefSettings,
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amount: briefAmount,
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journey: FuelSavingsJourney(miles: 7.6, basis: .roadRoute),
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baselineJourney: FuelSavingsJourney(miles: 0.8, basis: .roadRoute)
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)
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XCTAssertEqual(availability?.result?.distanceBasis, .roadRoute)
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XCTAssertEqual(availability?.result?.headline(compact: true), "£0.33 worse off after travel")
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XCTAssertEqual(availability?.result?.headline(), "£0.33 worse off after travel")
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}
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func testBaselineRowIsLabelledClosestStation() {
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let baseline = station("nearest", price: 171.9)
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let availability = FuelSavingsEstimator.availability(
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station: baseline,
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fuel: .e10,
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baseline: baseline,
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settings: briefSettings,
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amount: briefAmount,
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journey: straightLine(0.8),
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baselineJourney: straightLine(0.8)
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)
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XCTAssertEqual(availability?.result?.status, .baseline)
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XCTAssertEqual(availability?.result?.headline(compact: true), "Closest station")
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XCTAssertEqual(FuelSavingsStatus.baseline.displayName, "Closest station")
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XCTAssertEqual(availability?.result?.netSavingGBP, 0)
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XCTAssertEqual(availability?.result?.extraDistanceMiles, 0)
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}
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func testPositiveResultHeadlineSaysSaveAfterTravel() {
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// 4p cheaper AND almost the same distance, so the saving survives travel.
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let baseline = station("baseline", price: 160.0)
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let candidate = station("candidate", price: 150.0)
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let availability = FuelSavingsEstimator.availability(
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station: candidate,
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fuel: .e10,
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baseline: baseline,
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settings: briefSettings,
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amount: briefAmount,
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journey: straightLine(6.4),
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baselineJourney: straightLine(6.0)
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)
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guard let result = availability?.result else {
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return XCTFail("expected an estimate, got \(String(describing: availability))")
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}
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XCTAssertEqual(result.status, .worthTheDrive)
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// £60 buys 37.5 L at 160p; 10p/litre cheaper saves £3.75; 0.4 extra
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// return miles cost ~£0.09. Net ≈ £3.66.
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XCTAssertEqual(result.netSavingGBP, 3.659, accuracy: 0.005)
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XCTAssertEqual(result.headline(compact: true), "Save £3.66 after travel (est.)")
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}
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func testNeutralResultHeadlineIsBreakEven() {
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// 0.1p cheaper over the same distance: inside the break-even tolerance.
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let baseline = station("baseline", price: 150.0)
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let candidate = station("candidate", price: 149.9)
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let availability = FuelSavingsEstimator.availability(
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station: candidate,
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fuel: .e10,
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baseline: baseline,
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settings: briefSettings,
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amount: briefAmount,
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journey: straightLine(6.0),
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baselineJourney: straightLine(6.0)
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)
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XCTAssertEqual(availability?.result?.status, .breakEven)
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XCTAssertEqual(availability?.result?.headline(compact: true), "Break even")
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XCTAssertEqual(availability?.result?.headline(), "Break even")
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}
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/// The exact strings the brief asks for.
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func testHeadlineWordingMatchesTheBrief() {
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XCTAssertEqual(FuelSavingsResult.baselineHeadline, "Closest station")
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XCTAssertEqual(FuelSavingsResult.breakEvenHeadline, "Break even")
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let saving = FuelSavingsResult(fillLitres: 34.9,
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grossSavingGBP: 1.40,
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extraDrivingCostGBP: 0.88,
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extraDistanceMiles: 3.5,
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netSavingGBP: 0.52,
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status: .worthTheDrive,
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distanceBasis: .roadRoute)
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XCTAssertEqual(saving.headline(), "Save £0.52 after travel")
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let loss = FuelSavingsResult(fillLitres: 34.9,
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grossSavingGBP: 1.40,
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extraDrivingCostGBP: 1.71,
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extraDistanceMiles: 6.8,
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netSavingGBP: -0.31,
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status: .notWorthTheDrive,
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distanceBasis: .roadRoute)
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XCTAssertEqual(loss.headline(), "£0.31 worse off after travel")
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}
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/// The sort must order by NET saving, not pump price: a pricier station can
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/// win when the cheaper one is far enough away.
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func testSortingRanksByNetSavingNotPumpPrice() {
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let baseline = station("baseline", price: 171.9)
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let cheapButFar = station("cheap-but-far", price: 167.9)
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let pricierButNear = station("pricier-but-near", price: 169.9)
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let ranked = FuelSavingsEstimator.ranked(
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[baseline, cheapButFar, pricierButNear],
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fuel: .e10,
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baseline: baseline,
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settings: briefSettings,
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amount: briefAmount,
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journeyMiles: { s in
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switch s.id {
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case "baseline": return self.straightLine(0.8)
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case "cheap-but-far": return self.straightLine(7.6)
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default: return self.straightLine(1.2)
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}
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}
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)
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XCTAssertEqual(ranked.first?.id, "pricier-but-near",
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"net saving decides the order, not the pump price")
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XCTAssertEqual(ranked.last?.id, "cheap-but-far")
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}
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// MARK: Row copy
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/// The row's extra-driving caption must follow the DISPLAY unit: the stored
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/// figure is always miles, and converting by the current unit instead would
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/// leave a km user's figure unlabelled and 1.6× too large.
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func testExtraTravelLabelFollowsTheDisplayUnit() {
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XCTAssertEqual(
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FuelSavingsFormat.extraTravelLabel(extraDistanceMiles: 19.9, unit: .miles),
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"19.9 mi more driving than closest"
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)
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XCTAssertEqual(
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FuelSavingsFormat.extraTravelLabel(extraDistanceMiles: 19.9, unit: .kilometers),
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"32.0 km more driving than closest"
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)
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XCTAssertNil(FuelSavingsFormat.extraTravelLabel(extraDistanceMiles: 0, unit: .miles),
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"the baseline row has no extra travel to report")
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// The same conversion backs the detail sheet's extra-distance figure,
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// which used to be hardcoded miles ("%.1f miles") for km users too.
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XCTAssertEqual(FuelSavingsFormat.distance(19.9, unit: .miles), "19.9 mi")
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XCTAssertEqual(FuelSavingsFormat.distance(19.9, unit: .kilometers), "32.0 km")
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}
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/// The baseline capsule has to say what it IS: it previously repeated the
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/// status word above it ("Closest station" twice) and never explained that
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/// the savings are measured against it.
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func testCapsuleHeadlineMarksTheBaselineAndKeepsTheEstimateMarker() {
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let baseline = FuelSavingsResult(
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fillLitres: 30,
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grossSavingGBP: 0,
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extraDrivingCostGBP: 0,
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extraDistanceMiles: 0,
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netSavingGBP: 0,
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status: .baseline
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)
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XCTAssertEqual(baseline.capsuleHeadline(), "Closest station · your baseline")
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let saving = FuelSavingsResult(
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fillLitres: 30,
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grossSavingGBP: 2.40,
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extraDrivingCostGBP: 1.40,
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extraDistanceMiles: 5.2,
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netSavingGBP: 1.00,
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status: .worthTheDrive,
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distanceBasis: .straightLine
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)
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XCTAssertEqual(saving.capsuleHeadline(), "Save £1.00 after travel (est.)")
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let worse = FuelSavingsResult(
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fillLitres: 30,
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grossSavingGBP: 1.40,
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extraDrivingCostGBP: 1.70,
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extraDistanceMiles: 6.7,
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netSavingGBP: -0.31,
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status: .notWorthTheDrive
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)
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XCTAssertEqual(worse.capsuleHeadline(), "£0.31 worse off after travel")
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}
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}
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