Add some test utility functions for Windows

This allows detecting the components present within a Visual Studio installation for better test control.

Author: jakepetroules

Sources/SWBWindowsPlatform/Plugin.swift

@@ -11,7 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 public import SWBUtil
-import SWBCore
+public import SWBCore
 import Foundation
 
 @PluginExtensionSystemActor public func initializePlugin(_ manager: PluginManager) {
@@ -22,10 +22,10 @@ import Foundation
     manager.register(WindowsSDKRegistryExtension(), type: SDKRegistryExtensionPoint.self)
 }
 
-final class WindowsPlugin: Sendable {
+public final class WindowsPlugin: Sendable {
     private let vsInstallations = AsyncSingleValueCache<[VSInstallation], any Error>()
 
-    func cachedVSInstallations() async throws -> [VSInstallation] {
+    public func cachedVSInstallations() async throws -> [VSInstallation] {
         try await vsInstallations.value {
             // Always pass localFS because this will be cached, and executes a process on the host system so there's no reason to pass in any proxy.
             try await VSInstallation.findInstallations(fs: localFS)
@@ -39,10 +39,10 @@ struct WindowsPlatformSpecsExtension: SpecificationsExtension {
     }
 }
 
-struct WindowsEnvironmentExtension: EnvironmentExtension {
-    let plugin: WindowsPlugin
+@_spi(Testing) public struct WindowsEnvironmentExtension: EnvironmentExtension {
+    public let plugin: WindowsPlugin
 
-    func additionalEnvironmentVariables(context: any EnvironmentExtensionAdditionalEnvironmentVariablesContext) async throws -> [String: String] {
+    @_spi(Testing) public func additionalEnvironmentVariables(context: any EnvironmentExtensionAdditionalEnvironmentVariablesContext) async throws -> [String: String] {
         if context.hostOperatingSystem == .windows {
             // Add the environment variable for the MSVC toolset for Swift and Clang to find it
             let vcToolsInstallDir = "VCToolsInstallDir"

Sources/SWBWindowsPlatform/VSInstallation.swift

@@ -15,8 +15,29 @@ public import SWBUtil
 import SWBCore
 
 public struct VSInstallation: Decodable, Sendable {
+    public struct Component: Decodable, Sendable {
+        public struct ID: Decodable, Sendable, RawRepresentable {
+            public let rawValue: String
+
+            public init(_ string: String) {
+                self.rawValue = string
+            }
+
+            public init?(rawValue: String) {
+                self.rawValue = rawValue
+            }
+
+            public init(from decoder: any Swift.Decoder) throws {
+                rawValue = try String(from: decoder)
+            }
+        }
+
+        public let id: Component.ID
+    }
+
     public let installationPath: Path
     public let installationVersion: Version
+    public let packages: [Component]
 
     /// Returns a list of all Visual Studio installations on the system, ordered from newest version and last installed to oldest.
     ///
@@ -31,6 +52,7 @@ public struct VSInstallation: Decodable, Sendable {
             "-prerelease",
             "-sort",
             "-format", "json",
+            "-include", "packages",
             "-utf8",
         ]
         let executionResult = try await Process.getOutput(url: URL(fileURLWithPath: vswhere.str), arguments: args)

Tests/SWBWindowsPlatformTests/WindowsTestSupport.swift

@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SWBCore
+@_spi(Testing) import SWBWindowsPlatform
+
+extension VSInstallation.Component.ID {
+    static let visualCppBuildTools_x86_x64 = Self("Microsoft.VisualStudio.Component.VC.Tools.x86.x64")
+    static let visualCppBuildTools_arm = Self("Microsoft.VisualStudio.Component.VC.Tools.ARM")
+    static let visualCppBuildTools_arm64 = Self("Microsoft.VisualStudio.Component.VC.Tools.ARM64")
+    static let visualCppBuildTools_arm64ec = Self("Microsoft.VisualStudio.Component.VC.Tools.ARM64EC")
+}
+
+extension Core {
+    func hasVisualStudioComponent(_ name: VSInstallation.Component.ID) async throws -> Bool {
+        try await pluginManager.extensions(of: EnvironmentExtensionPoint.self).compactMap({ $0 as? WindowsEnvironmentExtension }).first?.plugin.cachedVSInstallations().first?.packages.contains(where: { $0.id == name }) == true
+    }
+}