Implement #30: CGATS parser, canonical .ti3 writer, and dataset import.

- Add CGATSParser, CGATSWriter, and CGATSSummary under ICCeryCore/CGATS.
- Parse CTI3, CGATS.17, ISO28178, and CSV; synthesize COLOR_REP/DEVICE_CLASS.
- Scale RGB/CMYK device coordinates from 0-255 to 0-100 when needed.
- Round-trip parse, write, reparse with tab-delimited canonical .ti3.
- Wire `Import Dataset…` in Stage 1 to open-panel import, write .ti3, and
  jump to Stage 4/5 while keeping Stages 1-2 locked without .ti1/.ti2.
- Add CGATSParserTests and Milestone6CGATSUITests.importUsesOpenPanelNotSaveTi1.

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

Packages/ICCeryCore/Sources/ICCeryCore/CGATS/CGATSParser.swift

@@ -0,0 +1,372 @@
+import Foundation
+
+/// Errors that can occur while parsing CGATS-like data.
+public enum CGATSParseError: Error, Equatable {
+    case emptyFile
+    case missingBeginDataFormat
+    case missingEndDataFormat
+    case missingBeginData
+    case missingEndData
+    case missingNumberOfFields
+    case missingNumberOfSets
+    case unknownFieldName(String)
+    case malformedRow(line: Int, reason: String)
+    case nonNumericValue(field: String, value: String, line: Int)
+    case outOfBoundsValue(field: String, value: Double, line: Int)
+    case implausibleValue(field: String, value: Double, line: Int)
+    case incorrectArity(line: Int, expected: Int, got: Int)
+}
+
+/// One row of a CGATS dataset, keyed by canonical field name.
+public struct CGATSSample: Sendable, Equatable {
+    public var id: String
+    public var loc: String?
+    public var values: [String: String]
+
+    public init(id: String, loc: String? = nil, values: [String: String] = [:]) {
+        self.id = id
+        self.loc = loc
+        self.values = values
+    }
+}
+
+/// A parsed CGATS / CTI3 / CSV dataset.
+public struct CGATSDataset: Sendable, Equatable {
+    public var format: CGATSFormat
+    public var keywords: [String: String]
+    public var fieldNames: [String]
+    public var samples: [CGATSSample]
+    public var colorRep: String?
+    public var deviceClass: String?
+    public var targetInstrument: String?
+
+    public init(
+        format: CGATSFormat,
+        keywords: [String: String] = [:],
+        fieldNames: [String] = [],
+        samples: [CGATSSample] = [],
+        colorRep: String? = nil,
+        deviceClass: String? = nil,
+        targetInstrument: String? = nil
+    ) {
+        self.format = format
+        self.keywords = keywords
+        self.fieldNames = fieldNames
+        self.samples = samples
+        self.colorRep = colorRep
+        self.deviceClass = deviceClass
+        self.targetInstrument = targetInstrument
+    }
+}
+
+public enum CGATSFormat: String, Sendable, Equatable {
+    case cti3 = "CTI3"
+    case cgats17 = "CGATS.17"
+    case csv = "CSV"
+}
+
+/// Parser for CGATS.17, CTI3, ISO28178, and simple CSV datasets.
+public enum CGATSParser {
+
+    /// Parse the contents of a CGATS-like file.
+    public static func parse(
+        _ contents: String,
+        sourceURL: URL? = nil
+    ) throws(CGATSParseError) -> CGATSDataset {
+        guard !contents.isEmpty else { throw .emptyFile }
+
+        let ext = sourceURL?.pathExtension.lowercased() ?? ""
+        let isCSV = ext == "csv" || contents.trimmingCharacters(in: .whitespacesAndNewlines)
+            .hasPrefix("SAMPLE_ID,")
+
+        let (format, lines) = try preprocess(contents, isCSV: isCSV)
+
+        var formatStart: Int?
+        var formatEnd: Int?
+        var dataStart: Int?
+        var dataEnd: Int?
+        var keywords = [String: String]()
+
+        for (index, line) in lines.enumerated() {
+            switch Self.normalizedKeyword(line) {
+            case "BEGIN_DATA_FORMAT": formatStart = index
+            case "END_DATA_FORMAT":   formatEnd = index
+            case "BEGIN_DATA":        dataStart = index
+            case "END_DATA":          dataEnd = index
+            default:
+                if let (key, value) = parseKeyword(line) {
+                    keywords[key] = value
+                }
+            }
+        }
+
+        guard let formatStart, let formatEnd, formatEnd > formatStart + 1 else {
+            throw .missingBeginDataFormat
+        }
+        guard let dataStart, let dataEnd, dataEnd > dataStart + 1 else {
+            throw .missingBeginData
+        }
+
+        let rawFieldNames = splitFields(lines[formatStart + 1])
+        let fieldNames = rawFieldNames.map { canonicalFieldName($0) }
+
+        if let numberOfFields = keywords["NUMBER_OF_FIELDS"].flatMap(Int.init),
+           numberOfFields != fieldNames.count {
+            // Warn only; the data format line is the source of truth.
+        } else if keywords["NUMBER_OF_FIELDS"] == nil {
+            // Optional header; do not fail.
+        }
+
+        if let numberOfSets = keywords["NUMBER_OF_SETS"].flatMap(Int.init),
+           numberOfSets != dataEnd - dataStart - 1 {
+            // Warn only; the actual rows are the source of truth.
+        } else if keywords["NUMBER_OF_SETS"] == nil {
+            // Optional header; do not fail.
+        }
+
+        struct RawSample {
+            var id: String
+            var loc: String?
+            var numbers: [String: Double] = [:]
+            var strings: [String: String] = [:]
+            var lineIndex: Int
+        }
+
+        var rawSamples = [RawSample]()
+        var groupMax: [String: Double] = [:]
+
+        for offset in 1...(dataEnd - dataStart - 1) {
+            let lineIndex = dataStart + offset
+            let rawRow = splitFields(lines[lineIndex])
+            guard rawRow.count == fieldNames.count else {
+                throw .incorrectArity(line: lineIndex + 1, expected: fieldNames.count, got: rawRow.count)
+            }
+
+            var sample = RawSample(id: String(offset), lineIndex: lineIndex)
+            for (i, name) in fieldNames.enumerated() {
+                let raw = stripInlineComment(rawRow[i])
+                if isNumericField(name) {
+                    let cleaned = raw.trimmingCharacters(in: .whitespaces)
+                    if let number = parseNumber(cleaned) {
+                        sample.numbers[name] = number
+                        if let group = deviceGroup(name) {
+                            groupMax[group, default: 0] = max(groupMax[group, default: 0], number)
+                        }
+                    } else if !cleaned.isEmpty {
+                        throw .nonNumericValue(field: name, value: raw, line: lineIndex + 1)
+                    }
+                } else {
+                    sample.strings[name] = raw
+                }
+            }
+
+            sample.id = sample.strings["SAMPLE_ID"] ?? sample.numbers["SAMPLE_ID"].map { String(format: "%.0f", $0) } ?? String(offset)
+            sample.loc = sample.strings["SAMPLE_LOC"]
+            rawSamples.append(sample)
+        }
+
+        var samples = [CGATSSample]()
+        for raw in rawSamples {
+            var values = raw.strings
+            for (name, number) in raw.numbers {
+                var scaled = number
+                if let group = deviceGroup(name), let maxValue = groupMax[group], maxValue > 100 {
+                    scaled = number / 2.55
+                }
+                values[name] = validateValue(scaled, field: name, line: raw.lineIndex + 1)
+            }
+
+            var sample = CGATSSample(id: raw.id, loc: raw.loc, values: values)
+            // Keep lookups by canonical keys, but also preserve original aliases.
+            let rawRow = splitFields(lines[raw.lineIndex])
+            for (i, rawName) in rawFieldNames.enumerated() {
+                let canonical = canonicalFieldName(rawName)
+                if canonical != rawName {
+                    sample.values[rawName] = rawRow[i]
+                }
+            }
+            samples.append(sample)
+        }
+
+        let colorRep = keywords["COLOR_REP"] ?? inferColorRep(fieldNames: fieldNames)
+        let deviceClass = keywords["DEVICE_CLASS"] ?? inferDeviceClass(fieldNames: fieldNames)
+
+        return CGATSDataset(
+            format: format,
+            keywords: keywords,
+            fieldNames: fieldNames,
+            samples: samples,
+            colorRep: colorRep,
+            deviceClass: deviceClass,
+            targetInstrument: keywords["TARGET_INSTRUMENT"]
+        )
+    }
+
+    /// Parse from a URL (throws as `Error` for public callers).
+    public static func parse(url: URL) throws -> CGATSDataset {
+        let contents = try String(contentsOf: url)
+        return try parse(contents, sourceURL: url)
+    }
+
+    // MARK: - Internals
+
+    private static func preprocess(
+        _ contents: String,
+        isCSV: Bool
+    ) throws(CGATSParseError) -> (CGATSFormat, [String]) {
+        let allLines = contents.components(separatedBy: .newlines)
+        var lines = [String]()
+
+        var format: CGATSFormat?
+        for var line in allLines {
+            line = stripComment(line)
+            line = line.trimmingCharacters(in: .whitespaces)
+            guard !line.isEmpty else { continue }
+
+            if format == nil {
+                if line.hasPrefix("CTI3") { format = .cti3 }
+                else if line.hasPrefix("CGATS.17") { format = .cgats17 }
+                else if isCSV { format = .csv }
+            }
+
+            if line == "BEGIN_DATA_FORMAT" || line == "END_DATA_FORMAT" ||
+               line == "BEGIN_DATA" || line == "END_DATA" ||
+               (line.hasPrefix("BEGIN_DATA_FORMAT") || line.hasPrefix("END_DATA_FORMAT") ||
+                line.hasPrefix("BEGIN_DATA") || line.hasPrefix("END_DATA")) {
+                // These are exact keywords; keep them intact.
+            }
+
+            lines.append(line)
+        }
+
+        guard !lines.isEmpty else { throw .emptyFile }
+
+        // Wrap a bare CSV / ISO28178 file in the canonical CGATS block
+        // structure so the boundary-based parser below can handle it.
+        if let format, format == .csv,
+           !lines.contains(where: { Self.normalizedKeyword($0) == "BEGIN_DATA_FORMAT" }) {
+            let header = lines[0]
+            let data = lines.dropFirst()
+            lines = [
+                "CTI3",
+                "BEGIN_DATA_FORMAT",
+                header,
+                "END_DATA_FORMAT",
+                "BEGIN_DATA"
+            ] + Array(data) + [
+                "END_DATA"
+            ]
+            return (.csv, lines)
+        }
+
+        return (format ?? .cti3, lines)
+    }
+
+    private static func stripComment(_ line: String) -> String {
+        if let range = line.range(of: "#") {
+            return String(line[..<range.lowerBound])
+        }
+        return line
+    }
+
+    private static func stripInlineComment(_ token: String) -> String {
+        if let range = token.range(of: "#") {
+            return String(token[..<range.lowerBound]).trimmingCharacters(in: .whitespaces)
+        }
+        return token
+    }
+
+    private static func splitFields(_ line: String) -> [String] {
+        // CTI3/CGATS.17 use whitespace/tabs; CSV uses commas.
+        if line.contains(",") {
+            return line.components(separatedBy: ",").map { $0.trimmingCharacters(in: .whitespaces) }
+        }
+        return line.components(separatedBy: .whitespaces).filter { !$0.isEmpty }
+    }
+
+    private static func parseKeyword(_ line: String) -> (key: String, value: String)? {
+        // KEYWORD value  or  KEYWORD "value"
+        let tokens = splitFields(line)
+        guard let key = tokens.first else { return nil }
+
+        // Data-boundary keywords are not value keywords.
+        let boundaryKeys = Set([
+            "BEGIN_DATA_FORMAT", "END_DATA_FORMAT",
+            "BEGIN_DATA", "END_DATA"
+        ])
+        guard !boundaryKeys.contains(key) else { return nil }
+
+        let rawValue = tokens.dropFirst().joined(separator: " ")
+        let value = rawValue.trimmingCharacters(in: CharacterSet(charactersIn: "\""))
+        return (key, value)
+    }
+
+    private static func normalizedKeyword(_ line: String) -> String {
+        line.uppercased().trimmingCharacters(in: .whitespaces)
+    }
+
+    // MARK: - Field name normalization
+
+    private static func canonicalFieldName(_ raw: String) -> String {
+        let upper = raw.uppercased()
+            .replacingOccurrences(of: " ", with: "_")
+            .replacingOccurrences(of: "-", with: "_")
+        switch upper {
+        case "SAMPLE_ID", "ID": return "SAMPLE_ID"
+        case "SAMPLE_LOC", "LOC": return "SAMPLE_LOC"
+        case "SAMPLE_NAME": return "SAMPLE_ID"
+        case "LAB_L", "L*", "L_AB": return "LAB_L"
+        case "LAB_A", "A*", "A_AB": return "LAB_A"
+        case "LAB_B", "B*", "B_AB": return "LAB_B"
+        case "XYZ_X", "X": return "XYZ_X"
+        case "XYZ_Y", "Y": return "XYZ_Y"
+        case "XYZ_Z", "Z": return "XYZ_Z"
+        default: return upper
+        }
+    }
+
+    private static func isNumericField(_ name: String) -> Bool {
+        let numericNames: Set = [
+            "SAMPLE_ID", "SAMPLE_LOC", "SAMPLE_NAME"
+        ]
+        return !numericNames.contains(name)
+    }
+
+    private static func parseNumber(_ raw: String) -> Double? {
+        let formatter = NumberFormatter()
+        formatter.numberStyle = .decimal
+        return formatter.number(from: raw)?.doubleValue
+    }
+
+    private static func validateValue(_ value: Double, field: String, line: Int) -> String {
+        var number = value
+
+        // Plausibility checks for Lab and XYZ.
+        if field == "LAB_L" { number = max(0, min(160, number)) }
+        if field == "LAB_A" || field == "LAB_B" { number = max(-128, min(128, number)) }
+        if field.hasPrefix("XYZ_") { number = max(0, min(200, number)) }
+
+        return String(format: "%.4f", number)
+    }
+
+    private static func deviceGroup(_ name: String) -> String? {
+        if name.hasPrefix("RGB_") { return "RGB" }
+        if name.hasPrefix("CMYK_") { return "CMYK" }
+        if name.hasPrefix("DEVICE_") { return "DEVICE" }
+        return nil
+    }
+
+    private static func inferColorRep(fieldNames: [String]) -> String? {
+        if fieldNames.contains(where: { $0.hasPrefix("CMYK_") }) { return "CMYK" }
+        if fieldNames.contains(where: { $0.hasPrefix("RGB_") }) { return "RGB" }
+        if fieldNames.contains(where: { $0.hasPrefix("LAB_") }) { return "LAB" }
+        if fieldNames.contains(where: { $0.hasPrefix("XYZ_") }) { return "XYZ" }
+        return nil
+    }
+
+    private static func inferDeviceClass(fieldNames: [String]) -> String? {
+        if fieldNames.contains(where: { $0.hasPrefix("CMYK_") }) { return "PRINTER" }
+        if fieldNames.contains(where: { $0.hasPrefix("RGB_") }) { return "DISPLAY" }
+        return "OUTPUT"
+    }
+}

Packages/ICCeryCore/Sources/ICCeryCore/CGATS/CGATSSummary.swift

@@ -0,0 +1,20 @@
+import Foundation
+
+/// Human-readable summary of an imported CGATS dataset.
+public struct CGATSSummary: Sendable, Equatable {
+    public let patchCount: Int
+    public let colorSpace: String?
+    public let deviceClass: String?
+    public let hasSpectral: Bool
+    public let previewRows: [String]
+
+    public init(dataset: CGATSDataset, previewRowCount: Int = 4) {
+        self.patchCount = dataset.samples.count
+        self.colorSpace = dataset.colorRep
+        self.deviceClass = dataset.deviceClass
+        self.hasSpectral = dataset.fieldNames.contains { $0.hasPrefix("SPECTRAL_") }
+        self.previewRows = Array(dataset.samples.prefix(previewRowCount).map { sample in
+            "\(sample.id)" + (sample.loc.map { " \($0)" } ?? "")
+        })
+    }
+}

Packages/ICCeryCore/Sources/ICCeryCore/CGATS/CGATSWriter.swift

@@ -0,0 +1,82 @@
+import Foundation
+
+/// Errors from writing a canonical `.ti3` dataset.
+public enum CGATSWriterError: Error, Equatable {
+    case noSamples
+    case missingRequiredField(String)
+    case invalidValue(field: String, value: String)
+}
+
+/// Write a `CGATSDataset` to Argyll-consumable `.ti3` text.
+public enum CGATSWriter {
+
+    public static func write(_ dataset: CGATSDataset) throws -> String {
+        guard !dataset.samples.isEmpty, !dataset.fieldNames.isEmpty else {
+            throw CGATSWriterError.noSamples
+        }
+
+        var lines = [String]()
+
+        // Header
+        lines.append(dataset.format.rawValue)
+        lines.append("")
+
+        lines.append("DESCRIPTOR \"ICCery CGATS export\"")
+        if let colorRep = dataset.colorRep {
+            lines.append("COLOR_REP \"\(colorRep)\"")
+        }
+        if let deviceClass = dataset.deviceClass {
+            lines.append("DEVICE_CLASS \"\(deviceClass)\"")
+        }
+        if let instrument = dataset.targetInstrument {
+            lines.append("TARGET_INSTRUMENT \"\(instrument)\"")
+        }
+
+        lines.append("NUMBER_OF_FIELDS \(dataset.fieldNames.count)")
+        lines.append("NUMBER_OF_SETS \(dataset.samples.count)")
+        lines.append("")
+
+        lines.append("BEGIN_DATA_FORMAT")
+        lines.append(dataset.fieldNames.joined(separator: "\t"))
+        lines.append("END_DATA_FORMAT")
+        lines.append("")
+
+        lines.append("BEGIN_DATA")
+        for sample in dataset.samples {
+            let row = try dataset.fieldNames.map { field in
+                guard let raw = sample.values[field], !raw.isEmpty else {
+                    throw CGATSWriterError.missingRequiredField(field)
+                }
+                // Normalize numeric fields to a compact decimal.
+                if isNumeric(field) {
+                    return normalizedNumber(raw)
+                }
+                return raw
+            }
+            lines.append(row.joined(separator: "\t"))
+        }
+        lines.append("END_DATA")
+
+        return lines.joined(separator: "\n") + "\n"
+    }
+
+    public static func write(_ dataset: CGATSDataset, to url: URL) throws {
+        let text = try write(dataset)
+        try text.write(to: url, atomically: true, encoding: .utf8)
+    }
+
+    // MARK: - Internals
+
+    private static func isNumeric(_ field: String) -> Bool {
+        let nonNumeric: Set = ["SAMPLE_ID", "SAMPLE_LOC", "SAMPLE_NAME"]
+        return !nonNumeric.contains(field)
+    }
+
+    private static func normalizedNumber(_ raw: String) -> String {
+        guard let number = Double(raw) else { return raw }
+        if number == floor(number) {
+            return String(format: "%.0f", number)
+        }
+        return String(format: "%.4f", number)
+    }
+}

Sources/ICCery/AppEnvironment.swift

@@ -68,6 +68,8 @@ enum UITestHooks {
     static var existingTargetURL: URL? { url("ICCERY_TEST_EXISTING_TARGET") }
     /// `select_directory` result (working-directory browse).
     static var workDirURL: URL? { url("ICCERY_TEST_WORKDIR") }
+    /// Dataset import file (`.ti3`, `.txt`, `.cgats`, `.csv`).
+    static var datasetImportURL: URL? { url("ICCERY_TEST_DATASET_IMPORT") }
     /// Preset import file.
     static var presetImportURL: URL? { url("ICCERY_TEST_PRESET_IMPORT") }
     /// Preset export destination.

Sources/ICCery/Stage1View.swift

@@ -87,9 +87,8 @@ struct Stage1View: View {
                 Button("Working Dir…") { workflow.browseForWorkingDirectory() }
                 Button("Open Existing…") { workflow.openExistingTarget() }
                     .accessibilityIdentifier("btnOpenExisting")
-                Button("Import Dataset…") { /* CGATS import — #94, later */ }
+                Button("Import Dataset…") { workflow.importMeasurementDataset() }
                     .accessibilityIdentifier("btn-import-dataset")
-                    .disabled(true)
             }
             Text(workflow.targetDirectory?.path ?? "No working directory selected")
                 .font(.caption)

Sources/ICCery/TargetWorkflowViewModel.swift

@@ -243,6 +243,43 @@ final class TargetWorkflowViewModel {
 
     // MARK: - Issue 8: resume an existing target
 
+    /// `#btn-import-dataset` — open a measured dataset, write a canonical
+    /// `.ti3` to the working directory, and set the target (issue #30).
+    func importMeasurementDataset() {
+        let url = UITestHooks.isEnabled
+            ? UITestHooks.datasetImportURL
+            : fileDialogs.selectDatasetFile()
+        guard let url else { return }
+
+        do {
+            let dataset = try CGATSParser.parse(url: url)
+            guard let directory = targetDirectory ?? wizard.effectiveWorkingDirectory else {
+                wizard.showNotice("Choose a working directory before importing.", kind: .warning)
+                return
+            }
+
+            let stem = url.deletingPathExtension().lastPathComponent
+            let output = directory.appendingPathComponent("\(stem).ti3")
+            try CGATSWriter.write(dataset, to: output)
+
+            wizard.setTarget(basename: stem, workingDirectory: directory)
+            wizard.refreshGating()
+            wizard.showNotice("Imported \(dataset.samples.count) patches from \(url.lastPathComponent)")
+
+            if wizard.isUnlocked(.verifyInstall) {
+                wizard.go(to: .verifyInstall)
+            } else if wizard.isUnlocked(.buildProfile) {
+                wizard.go(to: .buildProfile)
+            } else {
+                wizard.showNotice("Imported dataset is not ready for profiling.", kind: .warning)
+            }
+        } catch let error as CGATSParseError {
+            wizard.showNotice("Import failed: \(error.localizedDescription)", kind: .error)
+        } catch {
+            wizard.showNotice("Import failed: \(error.localizedDescription)", kind: .error)
+        }
+    }
+
     /// `#btnOpenExisting` — open `.ti1`/`.ti2` (open dialog, #103).
     /// `.ti1` → Stage 2; `.ti2` → Stage 3 with the resume notice, but
     /// only when the sibling `.ti1` exists so the artefact gate holds.

Tests/ICCeryCoreTests/CGATSParserTests.swift

@@ -0,0 +1,134 @@
+import Foundation
+import Testing
+@testable import ICCeryCore
+
+@Suite("CGATS Parser & Writer")
+struct CGATSParserTests {
+
+    private static let canonicalCTI3 = """
+    CTI3
+    DESCRIPTOR "Sample target"
+    COLOR_REP "RGB"
+    DEVICE_CLASS "DISPLAY"
+    NUMBER_OF_FIELDS 11
+    NUMBER_OF_SETS 2
+    BEGIN_DATA_FORMAT
+    SAMPLE_ID\tSAMPLE_LOC\tRGB_R\tRGB_G\tRGB_B\tXYZ_X\tXYZ_Y\tXYZ_Z\tLAB_L\tLAB_A\tLAB_B
+    END_DATA_FORMAT
+    BEGIN_DATA
+    1\tA1\t50.0\t0.0\t0.0\t20.0\t10.0\t5.0\t50.0\t60.0\t30.0
+    2\tA2\t0.0\t50.0\t0.0\t10.0\t30.0\t5.0\t60.0\t-50.0\t40.0
+    END_DATA
+    """
+
+    @Test("Parses CTI3 with canonical field names")
+    func parseCTI3() throws {
+        let dataset = try CGATSParser.parse(Self.canonicalCTI3)
+        #expect(dataset.format == .cti3)
+        #expect(dataset.samples.count == 2)
+        #expect(dataset.colorRep == "RGB")
+        #expect(dataset.deviceClass == "DISPLAY")
+        #expect(dataset.samples[0].id == "1")
+        #expect(dataset.samples[0].loc == "A1")
+        #expect(dataset.samples[1].values["RGB_G"] == "50.0000")
+    }
+
+    @Test("Round-trips parse, write, reparse")
+    func roundTrip() throws {
+        let first = try CGATSParser.parse(Self.canonicalCTI3)
+        let text = try CGATSWriter.write(first)
+        let second = try CGATSParser.parse(text)
+        #expect(second.format == first.format)
+        #expect(second.samples.count == first.samples.count)
+        #expect(second.colorRep == first.colorRep)
+        #expect(second.deviceClass == first.deviceClass)
+    }
+
+    @Test("Parses CSV with comma delimiters")
+    func parseCSV() throws {
+        let csv = """
+        SAMPLE_ID,SAMPLE_LOC,RGB_R,RGB_G,RGB_B,XYZ_X,XYZ_Y,XYZ_Z,LAB_L,LAB_A,LAB_B
+        1,A1,50,0,0,20,10,5,50,60,30
+        2,A2,0,50,0,10,30,5,60,-50,40
+        """
+        let dataset = try CGATSParser.parse(csv, sourceURL: URL(fileURLWithPath: "/tmp/sample.csv"))
+        #expect(dataset.format == .csv)
+        #expect(dataset.samples.count == 2)
+        #expect(dataset.samples[0].values["RGB_R"] == "50.0000")
+    }
+
+    @Test("Converts 0-255 device values to 0-100")
+    func converts255To100() throws {
+        let rgb = """
+        CTI3
+        COLOR_REP RGB
+        NUMBER_OF_FIELDS 6
+        NUMBER_OF_SETS 1
+        BEGIN_DATA_FORMAT
+        SAMPLE_ID RGB_R RGB_G RGB_B XYZ_X XYZ_Y
+        END_DATA_FORMAT
+        BEGIN_DATA
+        1 255 128 0 50 25
+        END_DATA
+        """
+        let dataset = try CGATSParser.parse(rgb)
+        #expect(dataset.samples[0].values["RGB_R"] == "100.0000")
+        #expect(dataset.samples[0].values["RGB_G"] == "50.1961")
+    }
+
+    @Test("Synthesizes COLOR_REP and DEVICE_CLASS when missing")
+    func synthesizesMetadata() throws {
+        let cmyk = """
+        CTI3
+        NUMBER_OF_FIELDS 6
+        NUMBER_OF_SETS 1
+        BEGIN_DATA_FORMAT
+        SAMPLE_ID CMYK_C CMYK_M CMYK_Y CMYK_K LAB_L
+        END_DATA_FORMAT
+        BEGIN_DATA
+        1 50 50 50 50 50
+        END_DATA
+        """
+        let dataset = try CGATSParser.parse(cmyk)
+        #expect(dataset.colorRep == "CMYK")
+        #expect(dataset.deviceClass == "PRINTER")
+    }
+
+    @Test("Rejects empty file")
+    func rejectsEmpty() {
+        #expect(throws: (any Error).self) {
+            _ = try CGATSParser.parse("")
+        }
+    }
+
+    @Test("Rejects malformed arity")
+    func rejectsArity() {
+        let bad = """
+        CTI3
+        NUMBER_OF_FIELDS 2
+        NUMBER_OF_SETS 1
+        BEGIN_DATA_FORMAT
+        SAMPLE_ID RGB_R
+        END_DATA_FORMAT
+        BEGIN_DATA
+        1
+        END_DATA
+        """
+        #expect(throws: (any Error).self) {
+            _ = try CGATSParser.parse(bad)
+        }
+    }
+
+    @Test("Writer emits valid .ti3 with tabs and required keywords")
+    func writerFormat() throws {
+        let dataset = try CGATSParser.parse(Self.canonicalCTI3)
+        let text = try CGATSWriter.write(dataset)
+        #expect(text.contains("CTI3"))
+        #expect(text.contains("BEGIN_DATA_FORMAT"))
+        #expect(text.contains("BEGIN_DATA"))
+        #expect(text.contains("END_DATA"))
+        #expect(text.contains("COLOR_REP"))
+        #expect(text.contains("DEVICE_CLASS"))
+        #expect(text.contains("\t"))
+    }
+}

Tests/ICCeryUITests/Milestone6CGATSUITests.swift

@@ -0,0 +1,64 @@
+import Foundation
+import XCTest
+
+/// Milestone 6 CGATS import UI tests (issue #30).
+@MainActor
+final class Milestone6CGATSUITests: XCTestCase {
+
+    private var app: XCUIApplication!
+    private var testRoot: URL!
+    private var datasetURL: URL!
+
+    override func setUp() async throws {
+        continueAfterFailure = false
+
+        testRoot = FileManager.default.temporaryDirectory
+            .appendingPathComponent("iccery-cgats-ui-\(UUID().uuidString)")
+        try FileManager.default.createDirectory(at: testRoot, withIntermediateDirectories: true)
+
+        let csv = """
+        SAMPLE_ID,SAMPLE_LOC,RGB_R,RGB_G,RGB_B,XYZ_X,XYZ_Y,XYZ_Z,LAB_L,LAB_A,LAB_B
+        1,A1,50,0,0,20,10,5,50,60,30
+        2,A2,0,50,0,10,30,5,60,-50,40
+        """
+        datasetURL = testRoot.appendingPathComponent("imported.csv")
+        try csv.write(to: datasetURL, atomically: true, encoding: .utf8)
+
+        app = XCUIApplication()
+        app.launchEnvironment = [
+            "ICCERY_UI_TESTING": "1",
+            "ICCERY_TEST_WORKDIR": testRoot.path,
+            "ICCERY_TEST_DATASET_IMPORT": datasetURL.path
+        ]
+    }
+
+    override func tearDown() async throws {
+        app?.terminate()
+        app = nil
+        if let testRoot {
+            try? FileManager.default.removeItem(at: testRoot)
+        }
+    }
+
+    /// `Milestone6CGATSUITests.importUsesOpenPanelNotSaveTi1`
+    /// Must fail if import presents a save panel or a `.ti1` filter.
+    func testImportUsesOpenPanelNotSaveTi1() throws {
+        app.launch()
+        app.activate()
+
+        XCTAssertTrue(app.buttons["btn-import-dataset"].waitForExistence(timeout: 10))
+        app.buttons["btn-import-dataset"].click()
+
+        // No save panel should appear; the open panel is stubbed under UI testing.
+        let savePanel = app.sheets.firstMatch
+        XCTAssertFalse(savePanel.exists, "Import must use an open panel, never a save panel.")
+
+        // The dataset should be accepted and the user should advance to Stage 4.
+        _ = app.otherElements["stage-4"].waitForExistence(timeout: 10)
+        XCTAssertTrue(app.otherElements["stage-4"].exists)
+
+        // The canonical .ti3 should be written next to the source file.
+        let ti3URL = testRoot.appendingPathComponent("imported.ti3")
+        XCTAssertTrue(FileManager.default.fileExists(atPath: ti3URL.path))
+    }
+}