Implemented the OpenProjectTask task in the library target.

Library/Sources/Public/Enumerations/IDE.swift

@@ -2,3 +2,19 @@ public enum IDE: String {
     case vscode
     case xcode
 }
+
+// MARK: - Extension
+
+extension IDE {
+    
+    // MARK: Functions
+    
+    static func random() -> IDE {
+        .allCases.randomElement() ?? .xcode
+    }
+    
+}
+
+// MARK: - CaseIterable
+
+extension IDE: CaseIterable {}

Library/Sources/Public/Tasks/OpenProjectTask.swift

@@ -0,0 +1,44 @@
+import Foundation
+
+public struct OpenProjectTask {
+    
+    // MARK: Properties
+    
+    private let terminalService: TerminalServicing
+    
+    // MARK: Initialisers
+    
+    public init(terminalService: TerminalServicing) {
+        self.terminalService = terminalService
+    }
+    
+    // MARK: Functions
+    
+    public func callAsFunction(with ide: IDE, at location: URL? = nil) async throws (TerminalServiceError) {
+        let executableURL: URL = switch ide {
+        case .vscode: .init(at: "/usr/local/bin/code")
+        case .xcode: .init(at: "/usr/bin/open")
+        }
+        
+        let locationPath = switch ide {
+        case .vscode: location?.pathString ?? "."
+        case .xcode: location?.appendingPath(.Path.package).pathString ?? .Path.package
+        }
+        
+        let arguments: [String] = switch ide {
+        case .vscode: [locationPath]
+        case .xcode: ["-a", "Xcode", locationPath]
+        }
+
+        try await terminalService.run(executableURL, arguments: arguments)
+    }
+    
+}
+
+// MARK: - String+Constants
+
+private extension String {
+    enum Path {
+        static let package = "Package.swift"
+    }
+}

Test/Sources/Cases/Public/Tasks/OpenProjectTaskTests.swift

@@ -0,0 +1,56 @@
+import Foundation
+import Testing
+
+@testable import ColibriLibrary
+
+struct OpenProjectTaskTests {
+    
+    @Test(arguments: [nil, URL.someCurrentFolder])
+    func taskWithVSCodeIDE(at location: URL?) async throws {
+        // GIVEN
+        let terminalService = TerminalServiceSpy()
+        let task = OpenProjectTask(terminalService: terminalService)
+        
+        // WHEN
+        try await task(with: .vscode, at: location)
+        
+        // THEN
+        let executableURL = URL(at: "/usr/local/bin/code")
+        let arguments = [location?.pathString ?? "."]
+
+        #expect(terminalService.actions.count == 1)
+        #expect(terminalService.actions[0] == .ran(executableURL, arguments))
+    }
+    
+    @Test(arguments: [nil, URL.someCurrentFolder])
+    func taskWithXcodeIDE(at location: URL?) async throws {
+        // GIVEN
+        let terminalService = TerminalServiceSpy()
+        let task = OpenProjectTask(terminalService: terminalService)
+        
+        // WHEN
+        try await task(with: .xcode, at: location)
+        
+        // THEN
+        let locationPath = location?.appendingPath("Package.swift").pathString ?? "Package.swift"
+        let executableURL = URL(at: "/usr/bin/open")
+        let arguments = ["-a", "Xcode", locationPath]
+        
+        #expect(terminalService.actions.count == 1)
+        #expect(terminalService.actions[0] == .ran(executableURL, arguments))
+    }
+    
+    @Test(arguments: [nil, URL.someCurrentFolder], [TerminalServiceError.unexpected, .output(""), .captured("")])
+    func task(at location: URL?, throws error: TerminalServiceError) async throws {
+        // GIVEN
+        let terminalService = TerminalServiceMock(action: .error(error))
+        let task = OpenProjectTask(terminalService: terminalService)
+        
+        // WHEN
+        // THEN
+        await #expect(throws: error) {
+            try await task(with: .random(), at: location)
+        }
+    }
+    
+}