fix(presets): complete config mapping contracts (#82)

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

.gitignore

@@ -27,4 +27,5 @@ ICCery.xcodeproj/
 Release/
 notarization/
 build/
-docs/megaplans/
+docs/megaplans/*
+docs/megaplans

Packages/ICCeryCore/Sources/ICCeryCore/Files/JSONFileStore.swift

@@ -27,10 +27,7 @@ public struct JSONFileStore<T: Codable & Sendable>: Sendable {
         self.fileURL = fileURL
         self.corrupt = corrupt
         self.defaultValue = defaultValue
-        let encoder = JSONEncoder()
-        encoder.outputFormatting = [.prettyPrinted, .sortedKeys]
-        encoder.dateEncodingStrategy = dateEncoding
-        self.encoder = encoder
+        self.encoder = JSONEncoder.icceryPretty(dateEncoding: dateEncoding)
         let decoder = JSONDecoder()
         decoder.dateDecodingStrategy = dateDecoding
         self.decoder = decoder
@@ -75,10 +72,14 @@ public struct JSONFileStore<T: Codable & Sendable>: Sendable {
 }
 
 extension JSONEncoder {
-    /// Pretty-printed, sorted-keys encoder used by preset export.
-    public static func icceryPretty() -> JSONEncoder {
+    /// Shared pretty-printed, sorted-keys encoder used by `JSONFileStore`
+    /// and preset export.
+    static func icceryPretty(
+        dateEncoding: JSONEncoder.DateEncodingStrategy = .deferredToDate
+    ) -> JSONEncoder {
         let encoder = JSONEncoder()
         encoder.outputFormatting = [.prettyPrinted, .sortedKeys]
+        encoder.dateEncodingStrategy = dateEncoding
         return encoder
     }
 }

Packages/ICCeryCore/Sources/ICCeryCore/Profile/VerificationHistoryStore.swift

@@ -73,7 +73,11 @@ public actor VerificationHistoryStore {
     }
 
     /// Removes all history and updates disk.
+    ///
+    /// Loads the existing history first and propagates any load error so an
+    /// unparseable file is never overwritten.
     public func clear() throws {
+        try load()
         try write([])
         records = []
     }

Packages/ICCeryCore/Sources/ICCeryCore/Settings/PresetMapping.swift

@@ -14,7 +14,9 @@ extension TargenConfig {
             neutralSteps: preset.neutralSteps,
             neutralConcentration: preset.neutralConcentration,
             preconditioningProfile: preset.preconditioningProfile,
-            ofpsHighQuality: preset.ofpsHighQuality == true ? true : nil,
+            // An explicit `false` is preserved — distinguishable from a
+            // missing key; `-G` is only emitted for `true` (#82).
+            ofpsHighQuality: preset.ofpsHighQuality,
             ofpsAdaptation: preset.ofpsAdaptation,
             fullSpreadAlgorithm: preset.fullSpreadAlgorithm.flatMap { FullSpreadAlgorithm(presetValue: $0) }.flatMap { $0 == .ofps ? nil : $0 },
             totalInkLimit: preset.totalInkLimit,
@@ -109,6 +111,51 @@ extension ColprofConfig {
     }
 }
 
+/// User-facing FWA selection for the Stage 4 form, plus the two
+/// directions of `colprof_fwa` conversion centralised here so the view
+/// models carry no mapping switches of their own (#82).
+public enum ColprofFwaSelection: String, CaseIterable, Sendable, Equatable {
+    case none = "none"
+    case empty = ""
+    case D50 = "D50"
+    case D65 = "D65"
+    case custom = "custom"
+
+    public var displayName: String {
+        switch self {
+        case .none: return "None"
+        case .empty: return "Bare (-f)"
+        case .D50: return "D50"
+        case .D65: return "D65"
+        case .custom: return "Custom .sp"
+        }
+    }
+
+    /// Preset `colprof_fwa` → selection. `nil`/`"none"` map to `.none`,
+    /// `""` to `.empty`, `D50`/`D65` case-insensitively, and any other
+    /// string is a custom `.sp` path.
+    public init(presetValue: String?) {
+        switch presetValue?.lowercased() {
+        case nil, "none": self = .none
+        case "": self = .empty
+        case "d50": self = .D50
+        case "d65": self = .D65
+        default: self = .custom
+        }
+    }
+
+    /// Selection → `colprof_fwa` value. `.custom` returns `customPath`.
+    public func presetValue(customPath: String) -> String? {
+        switch self {
+        case .none: return nil
+        case .empty: return ""
+        case .D50: return "D50"
+        case .D65: return "D65"
+        case .custom: return customPath
+        }
+    }
+}
+
 extension PageSize {
     /// `"210x297"` custom page parse used by presets (issue #82).
     public static func parseCustom(_ raw: String) -> (Double, Double)? {

README.md

@@ -11,7 +11,8 @@ All measurement, chart generation, and profile mathematics live in the [Gronod A
 | Floor | macOS 14 Sonoma, universal `arm64` + `x86_64` |
 | Default branch | `develop` |
 | M6 | Stage 0 calibration, CGATS import, SceneKit gamut viewer, packaging — shipped on `develop` |
-| M7 | UAT-ready hardening of the v2.0 wizard paths |
+| M7 | Pre-UAT hardening & baseline consolidation — shipped on `develop` |
+| M8 | Deduplication/consolidation contracts & UAT-ready hardening (#79–#86) — in flight on `milestone/m8-consolidation` |
 | Licence | Proprietary source in [`LICENCE.md`](LICENCE.md); bundled Argyll sidecars remain AGPLv3 |
 
 ## What it does
@@ -170,11 +171,11 @@ Agent / branch rules: [`AGENTS.md`](AGENTS.md), [`BUILD-PLAN.md`](BUILD-PLAN.md)
 
 ```
 develop
-  └── milestone/mN-<slug>          # integration only
+  └── milestone/m8-consolidation   # integration branch
         └── feat/<issue>-<slug>    # one issue per branch
 ```
 
-Feature PRs target the current milestone branch, not `develop`. The milestone branch merges to `develop` when its issues are green. M7 is small; its PRs target `develop` directly. Do not open umbrella "bugfix" branches that mix tickets.
+Feature PRs target the current milestone branch, not `develop`. The milestone branch merges to `develop` when its issues are green. Completion PRs for issues #79–#86 target `milestone/m8-consolidation`; `milestone/m8-consolidation` merges into `develop` once all milestone gates pass. Do not open umbrella "bugfix" branches that mix tickets.
 
 ## Licence
 

Sources/ICCery/ProfileWorkflowViewModel.swift

@@ -3,25 +3,6 @@ import Observation
 import SwiftUI
 import ICCeryCore
 
-/// User-facing FWA selection for the Stage 4 form.
-enum ColprofFwaSelection: String, CaseIterable, Sendable, Equatable {
-    case none = "none"
-    case empty = ""
-    case D50 = "D50"
-    case D65 = "D65"
-    case custom = "custom"
-
-    var displayName: String {
-        switch self {
-        case .none: return "None"
-        case .empty: return "Bare (-f)"
-        case .D50: return "D50"
-        case .D65: return "D65"
-        case .custom: return "Custom .sp"
-        }
-    }
-}
-
 /// Stage 4/5 workflow: build a profile, verify it, track drift, and install.
 @MainActor
 @Observable
@@ -110,13 +91,7 @@ final class ProfileWorkflowViewModel {
     }
 
     var fwaValue: String? {
-        switch fwaSelection {
-        case .none: return nil
-        case .empty: return ""
-        case .D50: return "D50"
-        case .D65: return "D65"
-        case .custom: return fwaCustomPath
-        }
+        fwaSelection.presetValue(customPath: fwaCustomPath)
     }
 
     // MARK: - Preset application
@@ -131,21 +106,16 @@ final class ProfileWorkflowViewModel {
         algorithm = config.algorithm
         quality = config.quality
         intent = config.intent ?? ""
-        if let fwa = config.fwa {
-            switch fwa.lowercased() {
-            case "none": fwaSelection = .none
-            case "": fwaSelection = .empty
-            case "d50": fwaSelection = .D50
-            case "d65": fwaSelection = .D65
-            default:
-                fwaSelection = .custom
-                fwaCustomPath = fwa
-            }
-        }
+        fwaSelection = ColprofFwaSelection(presetValue: config.fwa)
+        fwaCustomPath = fwaSelection == .custom ? (config.fwa ?? "") : ""
         illuminant = config.illuminant ?? ""
         observer = config.observer ?? ""
         inputViewingCond = config.inputViewingCond ?? ""
         outputViewingCond = config.outputViewingCond ?? ""
+        profileDescription = ""
+        copyright = ""
+        applyCalibration = preset.applyCalibration == true
+        calibrationFile = preset.calibrationFile ?? ""
     }
 
     /// Stage 4 form values for saving into a custom preset.

Sources/ICCery/TargetWorkflowViewModel.swift

@@ -380,14 +380,18 @@ final class TargetWorkflowViewModel {
     func applyPreset(_ preset: ProfilingPreset) {
         let targen = TargenConfig(preset: preset, basename: targetBasename, workingDirectory: targetDirectory)
         applyTargenForm(targen)
+        // Stage 4 state (incl. calibration) is applied before Stage 2 so
+        // the layout config receives the preset's calibration path, not
+        // stale live state (#82).
+        profile.applyPreset(preset)
         let printtarg = PrinttargConfig(
             preset: preset,
             basename: wizard.basename,
             workingDirectory: wizard.effectiveWorkingDirectory,
-            calibrationFile: profile.applyCalibration ? profile.calibrationFile : nil
+            calibrationFile: profile.applyCalibration && !profile.calibrationFile.isEmpty
+                ? profile.calibrationFile : nil
         )
         applyPrinttargForm(printtarg)
-        profile.applyPreset(preset)
         selectedPresetID = preset.id
     }
 

Tests/ICCeryCoreTests/JSONFileStoreTests.swift

@@ -9,7 +9,17 @@ struct JSONFileStoreTests {
             .appendingPathComponent("json-store-\(UUID().uuidString).json")
     }
 
-    @Test("Corrupt file with replaceWithDefault returns default")
+    @Test("Missing file returns default")
+    func missingFileDefaults() throws {
+        let store = JSONFileStore<AppSettings>(
+            fileURL: tempURL(),
+            corrupt: .throwCorrupt,
+            defaultValue: { .default }
+        )
+        #expect(try store.load() == .default)
+    }
+
+    @Test("Corrupt file with replaceWithDefault returns default and leaves bytes")
     func corruptDefaults() throws {
         let url = tempURL()
         try "{ not json".write(to: url, atomically: true, encoding: .utf8)
@@ -19,7 +29,8 @@ struct JSONFileStoreTests {
             defaultValue: { .default }
         )
         #expect(try store.load() == .default)
-        #expect(FileManager.default.fileExists(atPath: url.path))
+        let kept = try String(contentsOf: url, encoding: .utf8)
+        #expect(kept == "{ not json")
     }
 
     @Test("Corrupt file with throwCorrupt throws and leaves bytes")
@@ -50,6 +61,25 @@ struct JSONFileStoreTests {
         let text = try String(contentsOf: url, encoding: .utf8)
         #expect(text.contains("\n"))
         #expect(text.contains("\"delta_e_good_max\""))
+        // Lexical key sorting: ascending order of top-level keys.
+        let keys = [
+            "ask_before_overwrite_profile",
+            "calibration_stale_days",
+            "custom_presets",
+            "default_install_location",
+            "delta_e_good_max",
+            "delta_e_warning_max",
+            "enable_i1pro2_leds",
+            "open_color_panel_after_install",
+        ]
+        var lastIndex = text.startIndex
+        for key in keys {
+            guard let range = text.range(of: "\"\(key)\"", range: lastIndex..<text.endIndex) else {
+                Issue.record("missing or out-of-order key \(key)")
+                return
+            }
+            lastIndex = range.upperBound
+        }
     }
 }
 

Tests/ICCeryCoreTests/PresetTests.swift

@@ -287,4 +287,210 @@ struct PresetMappingTests {
         #expect(back.colprofFwa == "D50")
         #expect(back.greySteps == nil)
     }
+
+    @Test("Full preset round-trips through all three configs with every field asserted")
+    func fullRoundTrip() {
+        let preset = ProfilingPreset(
+            id: "custom-full",
+            name: "Full",
+            description: "All fields",
+            colourSpace: "cmyk",
+            patchCount: 1500,
+            whitePatches: 6,
+            blackPatches: 8,
+            greySteps: 9,
+            singleChannelSteps: 7,
+            neutralSteps: 4,
+            neutralConcentration: 0.7,
+            preconditioningProfile: "/tmp/pre.icm",
+            ofpsHighQuality: true,
+            ofpsAdaptation: 0.2,
+            fullSpreadAlgorithm: "R",
+            totalInkLimit: 280,
+            darkEmphasis: 1.3,
+            devicePower: 1.2,
+            instrument: "p3",
+            pageSize: "250x300",
+            bitDepth: 16,
+            dpi: 360,
+            randomSeed: 42,
+            noRandomize: false,
+            calibrationFile: "/tmp/a.cal",
+            applyCalibration: true,
+            colprofAlgorithm: "x",
+            colprofQuality: "u",
+            colprofIntent: "p",
+            colprofFwa: "D65",
+            colprofIlluminant: "D65",
+            colprofObserver: "1931_2",
+            colprofInputViewingCond: "D50_2",
+            colprofOutputViewingCond: "D65_2"
+        )
+
+        let targen = TargenConfig(preset: preset, basename: "j", workingDirectory: nil)
+        #expect(targen.colourSpace == .cmyk)
+        #expect(targen.patchCount == 1500)
+        #expect(targen.whitePatches == 6)
+        #expect(targen.blackPatches == 8)
+        #expect(targen.greySteps == 9)
+        #expect(targen.singleChannelSteps == 7)
+        #expect(targen.neutralSteps == 4)
+        #expect(targen.neutralConcentration == 0.7)
+        #expect(targen.preconditioningProfile == "/tmp/pre.icm")
+        #expect(targen.ofpsHighQuality == true)
+        #expect(targen.ofpsAdaptation == 0.2)
+        #expect(targen.fullSpreadAlgorithm == .uniformRandom)
+        #expect(targen.totalInkLimit == 280)
+        #expect(targen.darkEmphasis == 1.3)
+        #expect(targen.devicePower == 1.2)
+
+        let printtarg = PrinttargConfig(
+            preset: preset,
+            basename: "j",
+            workingDirectory: nil,
+            calibrationFile: preset.calibrationFile
+        )
+        #expect(printtarg.instrument == .p3)
+        #expect(printtarg.pageSize == .custom)
+        #expect(printtarg.customPageWidth == 250)
+        #expect(printtarg.customPageHeight == 300)
+        #expect(printtarg.bitDepth == .sixteen)
+        #expect(printtarg.dpi == 360)
+        #expect(printtarg.layoutOrder == .customSeed)
+        #expect(printtarg.customSeed == 42)
+        #expect(printtarg.calibrationFile == "/tmp/a.cal")
+
+        let colprof = ColprofConfig(preset: preset, basename: "j", workingDirectory: nil)
+        #expect(colprof.algorithm == "x")
+        #expect(colprof.quality == "u")
+        #expect(colprof.intent == "p")
+        #expect(colprof.fwa == "D65")
+        #expect(colprof.illuminant == "D65")
+        #expect(colprof.observer == "1931_2")
+        #expect(colprof.inputViewingCond == "D50_2")
+        #expect(colprof.outputViewingCond == "D65_2")
+
+        let back = ProfilingPreset(
+            id: preset.id,
+            name: preset.name,
+            description: preset.description,
+            targen: targen,
+            printtarg: printtarg,
+            colprof: colprof,
+            calibrationFile: preset.calibrationFile,
+            applyCalibration: preset.applyCalibration
+        )
+        #expect(back == preset)
+    }
+
+    @Test("Every full-spread algorithm round-trips", arguments: [
+        ("ofps", FullSpreadAlgorithm.ofps),
+        ("t", .target),
+        ("r", .random),
+        ("R", .uniformRandom),
+        ("q", .quasiRandom),
+        ("Q", .uniformQuasiRandom),
+        ("i", .invertedQuasiRandom),
+        ("I", .invertedUniformQuasiRandom)
+    ])
+    func fullSpreadAlgorithms(value: String, expected: FullSpreadAlgorithm) {
+        var preset = ProfilingPreset(id: "x", name: "n", patchCount: 100)
+        preset.fullSpreadAlgorithm = value
+        let cfg = TargenConfig(preset: preset, basename: "t", workingDirectory: nil)
+        if expected == .ofps {
+            // ofps is the default — no flag emitted, stored value is nil.
+            #expect(cfg.fullSpreadAlgorithm == nil)
+        } else {
+            #expect(cfg.fullSpreadAlgorithm == expected)
+        }
+        let back = ProfilingPreset(
+            id: "x", name: "n", description: "",
+            targen: cfg,
+            printtarg: PrinttargConfig(
+                preset: preset, basename: "t",
+                workingDirectory: nil, calibrationFile: nil
+            ),
+            colprof: ColprofConfig(preset: preset, basename: "t", workingDirectory: nil),
+            calibrationFile: nil,
+            applyCalibration: nil
+        )
+        #expect(back.fullSpreadAlgorithm == value)
+    }
+
+    @Test("Explicit ofpsHighQuality=false is preserved, distinct from nil")
+    func ofpsHighQualityFalse() {
+        var preset = ProfilingPreset(id: "x", name: "n", patchCount: 100)
+        preset.ofpsHighQuality = false
+        let cfg = TargenConfig(preset: preset, basename: "t", workingDirectory: nil)
+        #expect(cfg.ofpsHighQuality == false)
+
+        preset.ofpsHighQuality = nil
+        let nilCfg = TargenConfig(preset: preset, basename: "t", workingDirectory: nil)
+        #expect(nilCfg.ofpsHighQuality == nil)
+    }
+
+    @Test("noRandomize/seed layout mapping rules", arguments: [
+        (true, nil, LayoutOrder.raster, 1),
+        (true, 7, .raster, 7),
+        (false, nil, .deterministic, 1),
+        (false, 1, .deterministic, 1),
+        (nil, 1, .deterministic, 1),
+        (false, 5, .customSeed, 5)
+    ] as [(Bool?, Int?, LayoutOrder, Int)])
+    func layoutMapping(noRandomize: Bool?, seed: Int?, layout: LayoutOrder, expectedSeed: Int) {
+        var preset = ProfilingPreset(id: "x", name: "n", patchCount: 100)
+        preset.noRandomize = noRandomize
+        preset.randomSeed = seed
+        let cfg = PrinttargConfig(
+            preset: preset, basename: "t",
+            workingDirectory: nil, calibrationFile: nil
+        )
+        #expect(cfg.layoutOrder == layout)
+        #expect(cfg.customSeed == expectedSeed)
+    }
+
+    @Test("Custom page fallback matrix", arguments: [
+        ("250x300", PageSize.custom, 250.0, 300.0),
+        ("50x50", .custom, 50.0, 50.0),
+        ("foo", .a4, 210.0, 297.0),
+        ("30x40", .a4, 210.0, 297.0),
+        ("210x", .a4, 210.0, 297.0)
+    ] as [(String, PageSize, Double, Double)])
+    func customPageFallback(raw: String, page: PageSize, w: Double, h: Double) {
+        var preset = ProfilingPreset(id: "x", name: "n", patchCount: 100)
+        preset.pageSize = raw
+        let cfg = PrinttargConfig(
+            preset: preset, basename: "t",
+            workingDirectory: nil, calibrationFile: nil
+        )
+        #expect(cfg.pageSize == page)
+        #expect(cfg.customPageWidth == w)
+        #expect(cfg.customPageHeight == h)
+    }
+
+    @Test("FWA preset value → selection matrix", arguments: [
+        (nil, ColprofFwaSelection.none),
+        ("none", .none),
+        ("NONE", .none),
+        ("", .empty),
+        ("D50", .D50),
+        ("d50", .D50),
+        ("D65", .D65),
+        ("d65", .D65),
+        ("/tmp/fwa.sp", .custom)
+    ] as [(String?, ColprofFwaSelection)])
+    func fwaToSelection(raw: String?, expected: ColprofFwaSelection) {
+        #expect(ColprofFwaSelection(presetValue: raw) == expected)
+    }
+
+    @Test("FWA selection → preset value matrix", arguments: [
+        (ColprofFwaSelection.none, nil),
+        (.empty, ""),
+        (.D50, "D50"),
+        (.D65, "D65"),
+        (.custom, "/tmp/fwa.sp")
+    ] as [(ColprofFwaSelection, String?)])
+    func fwaToPresetValue(selection: ColprofFwaSelection, expected: String?) {
+        #expect(selection.presetValue(customPath: "/tmp/fwa.sp") == expected)
+    }
 }

Tests/ICCeryCoreTests/PresetViewModelMappingTests.swift

@@ -0,0 +1,127 @@
+import Testing
+import Foundation
+@testable import ICCeryCore
+@testable import ICCery
+
+/// Issue #82 — preset application through the live view models, under an
+/// isolated `TestAppEnvironment` (temp stores, fresh ProcessManager).
+@Suite("PresetViewModelMapping")
+@MainActor
+struct PresetViewModelMappingTests {
+
+    private func makeWorkflow() throws -> (TestAppEnvironment, TargetWorkflowViewModel) {
+        let env = try TestAppEnvironment.make()
+        return (env, TargetWorkflowViewModel(environment: env.environment))
+    }
+
+    @Test("Applying a nil-FWA preset after a custom FWA clears the stale path")
+    func nilFwaClearsCustomPath() throws {
+        let (env, vm) = try makeWorkflow()
+        defer { env.cleanup() }
+
+        var customPreset = ProfilingPreset(
+            id: "c-fwa", name: "FWA", patchCount: 800,
+            colprofFwa: "/tmp/fwa.sp"
+        )
+        vm.applyPreset(customPreset)
+        #expect(vm.profile.fwaSelection == .custom)
+        #expect(vm.profile.fwaCustomPath == "/tmp/fwa.sp")
+
+        customPreset.colprofFwa = nil
+        vm.applyPreset(customPreset)
+        #expect(vm.profile.fwaSelection == .none)
+        #expect(vm.profile.fwaCustomPath == "")
+        #expect(vm.profile.fwaValue == nil)
+    }
+
+    @Test("Custom FWA preset path survives the round-trip to colprof_fwa")
+    func customFwaRoundTrip() throws {
+        let (env, vm) = try makeWorkflow()
+        defer { env.cleanup() }
+
+        let preset = ProfilingPreset(
+            id: "c-fwa2", name: "FWA2", patchCount: 800,
+            colprofFwa: "/tmp/other.sp"
+        )
+        vm.applyPreset(preset)
+        #expect(vm.profile.fwaSelection == .custom)
+        #expect(vm.profile.fwaCustomPath == "/tmp/other.sp")
+        #expect(vm.profile.fwaValue == "/tmp/other.sp")
+    }
+
+    @Test("Preset calibration reaches Stage 2 instead of stale live state")
+    func presetCalibrationReachesStage2() throws {
+        let (env, vm) = try makeWorkflow()
+        defer { env.cleanup() }
+
+        // Stale live state must not leak into the preset-applied layout.
+        vm.profile.applyCalibration = true
+        vm.profile.calibrationFile = "/tmp/stale.cal"
+
+        let preset = ProfilingPreset(
+            id: "c-cal", name: "Cal", patchCount: 800,
+            calibrationFile: "/tmp/preset.cal",
+            applyCalibration: true
+        )
+        vm.applyPreset(preset)
+
+        #expect(vm.profile.applyCalibration)
+        #expect(vm.profile.calibrationFile == "/tmp/preset.cal")
+        #expect(vm.buildPrinttargConfig().calibrationFile == "/tmp/preset.cal")
+    }
+
+    @Test("Preset with calibration disabled clears Stage 2 calibration")
+    func disabledCalibrationClearsStage2() throws {
+        let (env, vm) = try makeWorkflow()
+        defer { env.cleanup() }
+
+        vm.profile.applyCalibration = true
+        vm.profile.calibrationFile = "/tmp/stale.cal"
+
+        let preset = ProfilingPreset(
+            id: "c-nocal", name: "NoCal", patchCount: 800,
+            calibrationFile: "/tmp/preset.cal",
+            applyCalibration: nil
+        )
+        vm.applyPreset(preset)
+
+        #expect(!vm.profile.applyCalibration)
+        #expect(vm.buildPrinttargConfig().calibrationFile == nil)
+    }
+
+    @Test("Preset Stage 1/2 form fields apply to the live form")
+    func formFieldsApply() throws {
+        let (env, vm) = try makeWorkflow()
+        defer { env.cleanup() }
+
+        var preset = ProfilingPreset(
+            id: "c-form", name: "Form",
+            colourSpace: "cmyk", patchCount: 1500,
+            whitePatches: 6,
+            blackPatches: 8,
+            greySteps: 9,
+            fullSpreadAlgorithm: "r",
+            pageSize: "250x300",
+            dpi: 150
+        )
+        vm.applyPreset(preset)
+
+        #expect(vm.colourSpace == .cmyk)
+        #expect(vm.effectivePatchCount == 1500)
+        #expect(vm.whitePatches == 6)
+        #expect(vm.blackPatches == 8)
+        #expect(vm.greyStepsEnabled && vm.greySteps == 9)
+        #expect(vm.algorithm == .random)
+        #expect(vm.tiffDpi == 150)
+        #expect(vm.pageSize == .custom)
+        #expect(vm.customPageW == 250 && vm.customPageH == 300)
+        #expect(vm.selectedPresetID == "c-form")
+
+        // Disabled advanced controls stay nil in the snapshot, not
+        // numeric sentinels.
+        preset.greySteps = nil
+        vm.applyPreset(preset)
+        #expect(!vm.greyStepsEnabled)
+        #expect(vm.buildTargenConfig().greySteps == nil)
+    }
+}

Tests/ICCeryCoreTests/SettingsTests.swift

@@ -93,6 +93,28 @@ struct SettingsStoreTests {
         #expect(!FileManager.default.fileExists(atPath: url.path))
     }
 
+    @Test func invalidSaveOverValidFilePreservesBytesAndPostsNothing() throws {
+        let url = tempStoreURL()
+        let store = SettingsStore(fileURL: url)
+        var valid = AppSettings.default
+        valid.deltaEGoodMax = 1.5
+        try store.save(valid)
+        let originalBytes = try Data(contentsOf: url)
+
+        var fired = false
+        let token = NotificationCenter.default.addObserver(
+            forName: SettingsStore.settingsDidChange, object: nil, queue: nil
+        ) { _ in fired = true }
+        defer { NotificationCenter.default.removeObserver(token) }
+
+        var invalid = AppSettings.default
+        invalid.deltaEGoodMax = 9.0
+        #expect(throws: SettingsStore.SettingsError.self) { try store.save(invalid) }
+        #expect(try Data(contentsOf: url) == originalBytes)
+        #expect(!fired)
+        #expect(store.load() == valid)
+    }
+
     @Test func savePostsNotification() async throws {
         let url = tempStoreURL()
         let store = SettingsStore(fileURL: url)

Tests/ICCeryCoreTests/TestAppEnvironment.swift

@@ -0,0 +1,62 @@
+import Testing
+import Foundation
+@testable import ICCeryCore
+@testable import ICCery
+
+/// Shared app-test dependency factory (issue #82).
+///
+/// Every store is pointed at a unique temporary directory so tests never
+/// read or write the user's real Application Support tree, and a fresh
+/// `ProcessManager` keeps child-process state isolated per test. The
+/// global process environment is never mutated.
+struct TestAppEnvironment {
+
+    /// Root temp directory holding all per-test state files.
+    let root: URL
+    let environment: AppEnvironment
+
+    var settingsURL: URL { root.appendingPathComponent("settings.json") }
+    var stateURL: URL { root.appendingPathComponent("wizard_state.json") }
+    var historyURL: URL {
+        root.appendingPathComponent("verification_history.json")
+    }
+
+    /// Creates an isolated environment under `NSTemporaryDirectory()`.
+    /// Call `cleanup()` when finished.
+    static func make() throws -> TestAppEnvironment {
+        let root = FileManager.default.temporaryDirectory
+            .appendingPathComponent("iccery-test-env-\(UUID().uuidString)")
+        try FileManager.default.createDirectory(
+            at: root, withIntermediateDirectories: true
+        )
+
+        let processManager = ProcessManager()
+        let settingsStore = SettingsStore(
+            fileURL: root.appendingPathComponent("settings.json")
+        )
+        let environment = AppEnvironment(
+            stateStore: WizardStateStore(
+                fileURL: root.appendingPathComponent("wizard_state.json")
+            ),
+            settingsStore: settingsStore,
+            presetStore: PresetStore(settingsStore: settingsStore),
+            runner: ArgyllRunner(
+                processManager: processManager,
+                binaryResolver: BinaryResolver(overrideDir: nil)
+            ),
+            cupsService: CupsService(
+                processManager: processManager,
+                binaryDir: root.appendingPathComponent("cups-bin")
+            ),
+            historyStore: VerificationHistoryStore(
+                url: root.appendingPathComponent("verification_history.json")
+            )
+        )
+        return TestAppEnvironment(root: root, environment: environment)
+    }
+
+    /// Removes the temporary root directory.
+    func cleanup() {
+        try? FileManager.default.removeItem(at: root)
+    }
+}

Tests/ICCeryCoreTests/VerificationHistoryStoreTests.swift

@@ -131,6 +131,57 @@ struct VerificationHistoryStoreTests {
         }
     }
 
+    @Test("Clear does not overwrite an unparseable file")
+    func clearPreservesUnparseableFile() async {
+        let fm = FileManager.default
+        let tmp = fm.temporaryDirectory.appendingPathComponent(UUID().uuidString)
+        try? fm.createDirectory(at: tmp, withIntermediateDirectories: true)
+        let url = tmp.appendingPathComponent("verification_history.json")
+
+        let badJSON = "not json"
+        try? badJSON.write(to: url, atomically: true, encoding: .utf8)
+
+        let store = VerificationHistoryStore(url: url)
+        do {
+            try await store.clear()
+            Issue.record("clear() should propagate the load error")
+        } catch {
+            let contents = try? String(contentsOf: url, encoding: .utf8)
+            #expect(contents == badJSON)
+        }
+    }
+
+    @Test("ISO-8601 timestamps round-trip through a fresh store")
+    func iso8601RoundTrip() async throws {
+        let fm = FileManager.default
+        let tmp = fm.temporaryDirectory.appendingPathComponent(UUID().uuidString)
+        try fm.createDirectory(at: tmp, withIntermediateDirectories: true)
+        let url = tmp.appendingPathComponent("verification_history.json")
+
+        let timestamp = Date(timeIntervalSince1970: 1_700_000_000)
+        let record = VerificationRecord(
+            id: "vr-iso",
+            profileName: "p",
+            printerName: "",
+            avgDE: 1.0,
+            maxDE: 2.0,
+            rmsDE: 1.5,
+            patchCount: 1,
+            status: .good,
+            timestamp: timestamp
+        )
+        let store1 = VerificationHistoryStore(url: url)
+        _ = try await store1.append(record)
+
+        let text = try String(contentsOf: url, encoding: .utf8)
+        #expect(text.contains(ISO8601DateFormatter().string(from: timestamp)))
+
+        let store2 = VerificationHistoryStore(url: url)
+        let loaded = try await store2.load()
+        #expect(loaded.count == 1)
+        #expect(loaded.first?.timestamp == timestamp)
+    }
+
     @Test("CSV export quoting")
     func csvQuoting() async throws {
         let fm = FileManager.default

Tests/ICCeryCoreTests/WizardGatingTests.swift

@@ -117,6 +117,17 @@ struct WizardStateStoreTests {
         #expect(WizardStateStore(fileURL: url).load().stage == .generate)
     }
 
+    @Test func corruptJsonReturnsDefaultAndKeepsBytes() throws {
+        let url = tempURL()
+        try FileManager.default.createDirectory(
+            at: url.deletingLastPathComponent(), withIntermediateDirectories: true
+        )
+        try "not json".write(to: url, atomically: true, encoding: .utf8)
+        #expect(WizardStateStore(fileURL: url).load() == .default)
+        let kept = try String(contentsOf: url, encoding: .utf8)
+        #expect(kept == "not json")
+    }
+
     @Test func sessionModeCalibrationRoundTrips() throws {
         var s = WizardState(sessionMode: .calibration)
         let data = try JSONEncoder().encode(s)