Bug fixes, unit tests, and SwiftArgumentParser migration

CLAUDE.md

@@ -0,0 +1,61 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+AckGen is an **Ack**nowledgements **Gen**erator that automatically extracts license information from Swift Package Manager dependencies and generates plist files for iOS/macOS apps.
+
+## Build Commands
+
+```bash
+# Build the CLI executable
+swift build
+
+# Build in release mode
+swift build -c release
+
+# Run the CLI (requires Xcode environment variables SRCROOT, PROJECT_TEMP_DIR)
+swift run ackgen --output <output_path> --settings --title <settingsTitle>
+
+# Run tests
+swift test
+
+# Bootstrap example project (requires mint)
+make bootstrap
+
+# Open example project in Xcode
+make open
+```
+
+## Architecture
+
+Three-module Swift Package with one external dependency (`swift-argument-parser` for the CLI):
+
+```
+AckGenCore (library)
+├── Acknowledgement.swift    # Model + plist decoding for runtime use
+│
+AckGenCLI (executable: ackgen)
+├── AckGen.swift             # Main logic: scans SourcePackages/checkouts for LICENSE files
+├── AcknowledgementsStringsTable.swift  # Settings.bundle plist format
+│
+AckGenUI (library)
+├── AcknowledgementsList.swift   # SwiftUI list view for displaying licenses
+```
+
+**Data Flow:**
+1. CLI runs as Xcode build phase, reads `PROJECT_TEMP_DIR` to find SPM checkouts
+2. Scans for LICENSE, LICENSE.txt, LICENSE.md in each package directory
+3. Encodes to plist (standard array or Settings.bundle format)
+4. App uses `Acknowledgement.all()` to decode plist at runtime
+
+**Two Output Formats:**
+- Standard: Array of `Acknowledgement` (default)
+- Settings Bundle: `AcknowledgementsStringsTable` format with `StringsTable` and `PreferenceSpecifiers` keys
+
+## Example App
+
+Located in `Example/`. Uses XcodeGen (`project.yml`) for project generation. Contains pre-build scripts demonstrating both plist formats:
+- `ackgen.sh` - Standard format
+- `ackgen_settings.sh` - Settings.bundle format

Example/ackgen.sh

@@ -4,7 +4,7 @@ DIR=..
 if [ -d "$DIR" ]; then
     cd $DIR
     SDKROOT=(xcrun --sdk macosx --show-sdk-path)
-    swift run ackgen $SRCROOT/PackageLicenses.plist
+    swift run ackgen --output "$SRCROOT/PackageLicenses.plist"
 else
     echo "warning: AckGen not found. Please install the package via SPM (https://github.com/MartinP7r/AckGen#installation)"
 fi

Example/ackgen_settings.sh

@@ -8,7 +8,7 @@ if [ -d "$DIR" ]; then
     if [ -d "$SETTINGS_BUNDLE" ]; then
         PLIST_PATH="$SETTINGS_BUNDLE/Acknowledgements.plist"
         PROJECT_NAME=$(basename "$SRCROOT")
-        swift run ackgen "$PLIST_PATH" 1 "$PROJECT_NAME"
+        swift run ackgen --output "$PLIST_PATH" --settings --title "$PROJECT_NAME"
     else
         echo "warning: Settings.bundle not found in the project."
     fi

Package.swift

@@ -16,13 +16,15 @@ let package = Package(
         .library(name: "AckGenUI", targets: ["AckGenUI"]),
     ],
     dependencies: [
-        // Dependencies declare other packages that this package depends on.
-        // .package(url: /* package url */, from: "1.0.0"),
+        .package(url: "https://github.com/apple/swift-argument-parser", from: "1.3.0"),
     ],
     targets: [
         .executableTarget(
             name: "AckGenCLI",
-            dependencies: ["AckGenCore"]),
+            dependencies: [
+                "AckGenCore",
+                .product(name: "ArgumentParser", package: "swift-argument-parser")
+            ]),
         .target(
             name: "AckGenUI",
             dependencies: ["AckGenCore"],
@@ -35,6 +37,7 @@ let package = Package(
         ),
         .testTarget(
             name: "AckGenTests",
-            dependencies: ["AckGenCore"]),
+            dependencies: ["AckGenCore"],
+            resources: [.copy("Fixtures")]),
     ]
 )

README.md

@@ -37,12 +37,20 @@ fi
 
 Make sure to set `ENABLE_USER_SCRIPT_SANDBOXING` to `NO` in your build settings so the build phase above can write to the desired destination.
 
-If you want the plist file to be saved somewhere other than `Acknowledgements.plist` at the root of your project (`$SRCROOT/Acknowledgements.plist`), you can provide a custom path as the first command line argument to `ackgen` above. 
+If you want the plist file to be saved somewhere other than `Acknowledgements.plist` at the root of your project (`$SRCROOT/Acknowledgements.plist`), you can provide a custom output path:
 
 ```sh
-  swift run ackgen $SRCROOT/PackageLicenses.plist
+  swift run ackgen --output "$SRCROOT/PackageLicenses.plist"
 ```
 
+To generate a Settings.bundle-compatible plist instead, use the `--settings` flag:
+
+```sh
+  swift run ackgen --output "$PLIST_PATH" --settings --title "MyApp"
+```
+
+Run `swift run ackgen --help` for all available options.
+
 3. Add the generated `plist` file to your project if you haven't already.  
 Make sure to remove the check for **Copy items if needed** 
 
@@ -96,5 +104,5 @@ make open
 - [x] Add UI components (SwiftUI List with NavigationLink to license info?)
 - [ ] Allow Run Script Output Files as alternative to command line argument
 - [ ] Allow to specify excluded packages
-- [ ] Add tests
+- [x] Add tests
 - [ ] Add other platforms

Sources/AckGenCLI/AckGen.swift

@@ -1,66 +1,82 @@
 //
 //  AckGen.swift
-//  
+//
 //
 //  Created by Martin Pfundmair on 2021-08-09.
 //
 
 import AckGenCore
+import ArgumentParser
 import Foundation
 
-struct AckGenCLI {
+@main
+struct AckGen: ParsableCommand {
+    static let configuration = CommandConfiguration(
+        abstract: "Generate acknowledgements plist from Swift Package Manager dependencies",
+        version: "0.8.0"
+    )
+
+    @Option(name: .shortAndLong, help: "Output path for the generated plist file")
+    var output: String?
+
+    @Flag(name: .long, help: "Generate Settings.bundle format")
+    var settings: Bool = false
 
-    static func main() {
+    @Option(name: .long, help: "Title for Settings.bundle (only used with --settings)")
+    var title: String = "Acknowledgements"
+
+    func run() throws {
         print("Generating Acknowledgements file")
 
         let licenseFiles: [String] = ["LICENSE", "LICENSE.txt", "LICENSE.md"]
-
-        let arguments: [String] = Array(CommandLine.arguments.dropFirst())
 
         guard let srcRoot = ProcessInfo.processInfo.environment["SRCROOT"] else {
-            print("error: could not detect the source root directory.")
-            return
+            throw ValidationError("Could not detect the source root directory (SRCROOT environment variable not set)")
         }
         guard let tempDirPath = ProcessInfo.processInfo.environment["PROJECT_TEMP_DIR"] else {
-            print("error: could not detect the project's temp directory.")
-            return
+            throw ValidationError("Could not detect the project's temp directory (PROJECT_TEMP_DIR environment variable not set)")
         }
 
-        let plistPath: String = arguments.first ?? "\(srcRoot)/Acknowledgements.plist"
-
-        let forSettings: Bool = arguments.count > 1
-
-        let settingsTitle: String = arguments.count > 2 ? arguments[2] : "Acknowledgements"
+        let plistPath: String = output ?? "\(srcRoot)/Acknowledgements.plist"
 
         let packageCachePath = tempDirPath.components(separatedBy: "/Build/")[0] + "/SourcePackages/checkouts"
         let fman = FileManager.default
 
-        do {
+        let packageDirectories = try fman.contentsOfDirectory(atPath: packageCachePath)
+        var acknowledgements = [Acknowledgement]()
 
-            let packageDirectories = try fman.contentsOfDirectory(atPath: packageCachePath)
-            var acknowledgements = [Acknowledgement]()
-
-            for pkgDir in packageDirectories where pkgDir.prefix(1) != "." {
-                for file in licenseFiles {
-                    guard let data = fman.contents(atPath: "\(packageCachePath)/\(pkgDir)/\(file)")  else { continue }
-                    let new = Acknowledgement(title: pkgDir, license: String(data: data, encoding: .utf8)!)
-                    acknowledgements.append(new)
+        for pkgDir in packageDirectories where pkgDir.prefix(1) != "." {
+            for file in licenseFiles {
+                guard let data = fman.contents(atPath: "\(packageCachePath)/\(pkgDir)/\(file)") else { continue }
+                guard let license = String(data: data, encoding: .utf8) else {
+                    print("warning: Skipping \(pkgDir)/\(file) - invalid UTF-8 encoding")
+                    continue
                 }
+                let new = Acknowledgement(title: pkgDir, license: license)
+                acknowledgements.append(new)
+                break
             }
+        }
+
+        if acknowledgements.isEmpty {
+            throw ValidationError(
+                "No license files found in \(packageCachePath). " +
+                "Ensure SPM packages are resolved (Xcode → File → Packages → Resolve)."
+            )
+        }
 
-            let encoder = PropertyListEncoder()
-            encoder.outputFormat = .xml
+        let encoder = PropertyListEncoder()
+        encoder.outputFormat = .xml
 
-            if forSettings {
-                let acknowledgementsSettings = AcknowledgementsStringsTable(name: settingsTitle, acknowledgements: acknowledgements)
-                let data = try encoder.encode(acknowledgementsSettings)
-                try data.write(to: URL(fileURLWithPath: plistPath))
-            } else {
-                let data = try encoder.encode(acknowledgements)
-                try data.write(to: URL(fileURLWithPath: plistPath))
-            }
-        } catch {
-            print(error)
+        if settings {
+            let acknowledgementsSettings = AcknowledgementsStringsTable(name: title, acknowledgements: acknowledgements)
+            let data = try encoder.encode(acknowledgementsSettings)
+            try data.write(to: URL(fileURLWithPath: plistPath))
+        } else {
+            let data = try encoder.encode(acknowledgements)
+            try data.write(to: URL(fileURLWithPath: plistPath))
         }
+
+        print("✓ Generated acknowledgements at: \(plistPath)")
     }
 }

Tests/AckGenTests/AcknowledgementAllTests.swift

@@ -0,0 +1,66 @@
+//
+//  AcknowledgementAllTests.swift
+//  AckGenTests
+//
+//  Created by Martin Pfundmair on 2026-01-13.
+//
+
+import XCTest
+@testable import AckGenCore
+
+final class AcknowledgementAllTests: XCTestCase {
+
+    func testAllDecodesFixturePlist() {
+        // Given: A fixture plist in the test bundle's Fixtures directory
+        // When: Loading acknowledgements from the fixture
+        let acks = Acknowledgement.all(fromPlist: "Fixtures/Acknowledgements", in: Bundle.module)
+
+        // Then: All entries should be decoded correctly
+        XCTAssertEqual(acks.count, 3)
+
+        // Verify the content is decoded properly
+        let titles = acks.map(\.title)
+        XCTAssertTrue(titles.contains("Zebra"))
+        XCTAssertTrue(titles.contains("apple"))
+        XCTAssertTrue(titles.contains("Banana"))
+
+        // Verify license content is present
+        let zebra = acks.first { $0.title == "Zebra" }
+        XCTAssertEqual(zebra?.license, "MIT License for Zebra package")
+    }
+
+    func testAllSortsCaseInsensitively() {
+        // Given: A fixture plist with mixed case titles (Zebra, apple, Banana)
+        // When: Loading acknowledgements (which applies case-insensitive sorting)
+        let acks = Acknowledgement.all(fromPlist: "Fixtures/Acknowledgements", in: Bundle.module)
+
+        // Then: Should be sorted case-insensitively: apple, Banana, Zebra
+        XCTAssertEqual(acks.count, 3)
+        XCTAssertEqual(acks[0].title, "apple")   // 'a' comes first
+        XCTAssertEqual(acks[1].title, "Banana")  // 'B' (as 'b') comes second
+        XCTAssertEqual(acks[2].title, "Zebra")   // 'Z' (as 'z') comes last
+    }
+
+    func testAllReturnsEmptyArrayForMissingPlist() {
+        // Given: A non-existent plist name
+        let bundle = Bundle.module
+
+        // When: Loading from a non-existent plist
+        let acks = Acknowledgement.all(fromPlist: "NonExistent", in: bundle)
+
+        // Then: Should return empty array instead of crashing
+        XCTAssertTrue(acks.isEmpty)
+    }
+
+    func testAllReturnsEmptyArrayForInvalidPlist() {
+        // Given: A malformed/invalid plist file (fixture: invalid-utf8-license)
+        // Note: This test verifies graceful handling of decode failures for malformed plist data
+        // The all() method should return an empty array for any plist decode failure
+
+        // When: Attempting to decode a malformed plist that cannot be parsed
+        let acks = Acknowledgement.all(fromPlist: "Fixtures/invalid-utf8-license", in: Bundle.module)
+
+        // Then: Should return empty array instead of crashing
+        XCTAssertTrue(acks.isEmpty)
+    }
+}