Non-darwin test discovery with Swift Build

Sources/SPMBuildCore/BuildParameters/BuildParameters.swift

@@ -314,11 +314,26 @@ public struct BuildParameters: Encodable {
         case .library(.automatic), .plugin:
             fatalError()
         case .test:
-            let base = "\(product.name).xctest"
-            if self.triple.isDarwin() {
-                return try RelativePath(validating: "\(base)/Contents/MacOS/\(product.name)")
-            } else {
-                return try RelativePath(validating: base)
+            switch buildSystemKind {
+            case .native, .xcode:
+                let base = "\(product.name).xctest"
+                if self.triple.isDarwin() {
+                    return try RelativePath(validating: "\(base)/Contents/MacOS/\(product.name)")
+                } else {
+                    return try RelativePath(validating: base)
+                }
+            case .swiftbuild:
+                if self.triple.isDarwin() {
+                    let base = "\(product.name).xctest"
+                    return try RelativePath(validating: "\(base)/Contents/MacOS/\(product.name)")
+                } else {
+                    var base = "\(product.name)-test-runner"
+                    let ext = self.triple.executableExtension
+                    if !ext.isEmpty {
+                        base += ".\(ext)"
+                    }
+                    return try RelativePath(validating: base)
+                }
             }
         case .macro:
             #if BUILD_MACROS_AS_DYLIBS

Sources/SPMBuildCore/BuiltTestProduct.swift

@@ -28,6 +28,10 @@ public struct BuiltTestProduct: Codable {
     /// When the test product is not bundled (for instance, when using XCTest on
     /// non-Darwin targets), this path is equal to ``binaryPath``.
     public var bundlePath: AbsolutePath {
+        // If the binary path is a test runner binary, return it as-is.
+        guard !binaryPath.basenameWithoutExt.hasSuffix("test-runner") else {
+            return binaryPath
+        }
         // Go up the folder hierarchy until we find the .xctest bundle.
         let pathExtension = ".xctest"
         let hierarchySequence = sequence(first: binaryPath, next: { $0.isRoot ? nil : $0.parentDirectory })

Sources/SwiftBuildSupport/PIFBuilder.swift

@@ -633,13 +633,13 @@ fileprivate func buildAggregateProject(
                         continue
                     }
                 }
-                
+
                 aggregateProject[keyPath: allIncludingTestsTargetKeyPath].common.addDependency(
                     on: target.id,
                     platformFilters: [],
                     linkProduct: false
                 )
-                if target.productType != .unitTest {
+                if ![.unitTest, .swiftpmTestRunner].contains(target.productType) {
                     aggregateProject[keyPath: allExcludingTestsTargetKeyPath].common.addDependency(
                         on: target.id,
                         platformFilters: [],

Sources/SwiftBuildSupport/PackagePIFBuilder+Helpers.swift

@@ -897,7 +897,7 @@ extension ProjectModel.BuildSettings {
                 // Appending implies the setting is resilient to having ["$(inherited)"]
                 self.platformSpecificSettings[platform]![setting]!.append(contentsOf: values)
 
-            case .SWIFT_VERSION:
+            case .SWIFT_VERSION, .DYLIB_INSTALL_NAME_BASE:
                 self.platformSpecificSettings[platform]![setting] = values // We are not resilient to $(inherited).
 
             case .ARCHS, .IPHONEOS_DEPLOYMENT_TARGET, .SPECIALIZATION_SDK_OPTIONS:
@@ -922,6 +922,9 @@ extension ProjectModel.BuildSettings {
             case .SWIFT_VERSION:
                 self[.SWIFT_VERSION] = values.only.unwrap(orAssert: "Invalid values for 'SWIFT_VERSION': \(values)")
 
+            case .DYLIB_INSTALL_NAME_BASE:
+                self[.DYLIB_INSTALL_NAME_BASE] = values.only.unwrap(orAssert: "Invalid values for 'DYLIB_INSTALL_NAME_BASE': \(values)")
+
             case .ARCHS, .IPHONEOS_DEPLOYMENT_TARGET, .SPECIALIZATION_SDK_OPTIONS:
                 fatalError("Unexpected BuildSettings.Declaration: \(setting)")
             // Allow staging in new cases
@@ -953,7 +956,7 @@ extension ProjectModel.BuildSettings.MultipleValueSetting {
             self = .SPECIALIZATION_SDK_OPTIONS
         case .SWIFT_ACTIVE_COMPILATION_CONDITIONS:
             self = .SWIFT_ACTIVE_COMPILATION_CONDITIONS
-        case .ARCHS, .IPHONEOS_DEPLOYMENT_TARGET, .SWIFT_VERSION:
+        case .ARCHS, .IPHONEOS_DEPLOYMENT_TARGET, .SWIFT_VERSION, .DYLIB_INSTALL_NAME_BASE:
             return nil
         // Allow staging in new cases
         default:

Sources/SwiftBuildSupport/PackagePIFBuilder.swift

@@ -362,6 +362,7 @@ public final class PackagePIFBuilder {
         case framework
         case executable
         case unitTest
+        case unitTestRunner
         case bundle
         case resourceBundle
         case packageProduct
@@ -385,6 +386,7 @@ public final class PackagePIFBuilder {
             case .framework: .framework
             case .executable: .executable
             case .unitTest: .unitTest
+            case .swiftpmTestRunner: .unitTestRunner
             case .bundle: .bundle
             case .packageProduct: .packageProduct
             case .hostBuildTool: fatalError("Unexpected hostBuildTool type")
@@ -520,7 +522,15 @@ public final class PackagePIFBuilder {
         settings[.WATCHOS_DEPLOYMENT_TARGET] = builder.deploymentTargets[.watchOS] ?? nil
         settings[.DRIVERKIT_DEPLOYMENT_TARGET] = builder.deploymentTargets[.driverKit] ?? nil
         settings[.XROS_DEPLOYMENT_TARGET] = builder.deploymentTargets[.visionOS] ?? nil
-        settings[.DYLIB_INSTALL_NAME_BASE] = "@rpath"
+
+        for machoPlatform in [ProjectModel.BuildSettings.Platform.macOS, .macCatalyst, .iOS, .watchOS, .tvOS, .xrOS, .driverKit] {
+            settings.platformSpecificSettings[machoPlatform]![.DYLIB_INSTALL_NAME_BASE]! = ["@rpath"]
+        }
+        for elfPlatform in [ProjectModel.BuildSettings.Platform.linux, .android, .openbsd, .freebsd] {
+            // FIXME: Treating $ORIGIN as part of the soname is not really the right thing to do here
+            settings.platformSpecificSettings[elfPlatform]![.DYLIB_INSTALL_NAME_BASE]! = ["$ORIGIN"]
+        }
+
         settings[.USE_HEADERMAP] = "NO"
         settings[.OTHER_SWIFT_FLAGS].lazilyInitializeAndMutate(initialValue: ["$(inherited)"]) { $0.append("-DXcode") }
 

Sources/SwiftBuildSupport/PackagePIFProjectBuilder+Products.swift

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 import Foundation
+import TSCBasic
 import TSCUtility
 
 import struct Basics.AbsolutePath
@@ -128,6 +129,8 @@ extension PackagePIFProjectBuilder {
             settings[.GENERATE_INFOPLIST_FILE] = "YES"
             settings[.SKIP_INSTALL] = "NO"
             settings[.SWIFT_ACTIVE_COMPILATION_CONDITIONS].lazilyInitialize { ["$(inherited)"] }
+            // Enable index-while building for Swift compilations to facilitate discovery of XCTest tests.
+            settings[.SWIFT_INDEX_STORE_ENABLE] = "YES"
         } else if mainModule.type == .executable {
             // Setup install path for executables if it's in root of a pure Swift package.
             if pifBuilder.delegate.hostsOnlyPackages && pifBuilder.delegate.isRootPackage {
@@ -502,9 +505,13 @@ extension PackagePIFProjectBuilder {
             linkedPackageBinaries: linkedPackageBinaries,
             swiftLanguageVersion: mainModule.packageSwiftLanguageVersion(manifest: packageManifest),
             declaredPlatforms: self.declaredPlatforms,
-            deploymentTargets: self.deploymentTargets
+            deploymentTargets: mainTargetDeploymentTargets
         )
         self.builtModulesAndProducts.append(moduleOrProduct)
+
+        if moduleOrProductType == .unitTest {
+            try makeTestRunnerProduct(for: moduleOrProduct)
+        }
     }
 
     private mutating func handleProduct(
@@ -995,6 +1002,102 @@ extension PackagePIFProjectBuilder {
         )
         self.builtModulesAndProducts.append(pluginProductMetadata)
     }
+
+    // MARK: - Test Runners
+    mutating func makeTestRunnerProduct(for unitTestProduct: PackagePIFBuilder.ModuleOrProduct) throws {
+        // Only generate a test runner for root packages with tests.
+        guard pifBuilder.delegate.isRootPackage else {
+            return
+        }
+
+        guard let unitTestModuleName = unitTestProduct.moduleName else {
+            throw StringError("Unit test product '\(unitTestProduct.name)' is missing a module name")
+        }
+
+        let name = "\(unitTestProduct.name)-test-runner"
+        let moduleName = "\(unitTestModuleName)_test_runner"
+        let guid = PackagePIFBuilder.targetGUID(forModuleName: moduleName)
+
+        let testRunnerTargetKeyPath = try self.project.addTarget { _ in
+            ProjectModel.Target (
+                id: guid,
+                productType: .swiftpmTestRunner,
+                name: name,
+                productName: name
+            )
+        }
+
+        var settings: BuildSettings = self.package.underlying.packageBaseBuildSettings
+        let impartedSettings = BuildSettings()
+
+        settings[.TARGET_NAME] = name
+        settings[.PACKAGE_RESOURCE_TARGET_KIND] = "regular"
+        settings[.PRODUCT_NAME] = "$(TARGET_NAME)"
+        settings[.PRODUCT_MODULE_NAME] = moduleName
+        settings[.PRODUCT_BUNDLE_IDENTIFIER] = "\(self.package.identity).\(name)"
+            .spm_mangledToBundleIdentifier()
+        settings[.EXECUTABLE_NAME] = name
+        settings[.SKIP_INSTALL] = "NO"
+        settings[.SWIFT_VERSION] = "5.0"
+        // This should eventually be set universally for all package targets/products.
+        settings[.LINKER_DRIVER] = "swiftc"
+
+        let deploymentTargets = unitTestProduct.deploymentTargets
+        settings[.MACOSX_DEPLOYMENT_TARGET] = deploymentTargets?[.macOS] ?? nil
+        settings[.IPHONEOS_DEPLOYMENT_TARGET] = deploymentTargets?[.iOS] ?? nil
+        if let deploymentTarget_macCatalyst = deploymentTargets?[.macCatalyst] ?? nil {
+            settings.platformSpecificSettings[.macCatalyst]![.IPHONEOS_DEPLOYMENT_TARGET] = [deploymentTarget_macCatalyst]
+        }
+        settings[.TVOS_DEPLOYMENT_TARGET] = deploymentTargets?[.tvOS] ?? nil
+        settings[.WATCHOS_DEPLOYMENT_TARGET] = deploymentTargets?[.watchOS] ?? nil
+        settings[.DRIVERKIT_DEPLOYMENT_TARGET] = deploymentTargets?[.driverKit] ?? nil
+        settings[.XROS_DEPLOYMENT_TARGET] = deploymentTargets?[.visionOS] ?? nil
+
+        // Add an empty sources phase so derived sources are compiled
+        self.project[keyPath: testRunnerTargetKeyPath].common.addSourcesBuildPhase { id in
+            ProjectModel.SourcesBuildPhase(id: id)
+        }
+
+        guard let unitTestGUID = unitTestProduct.pifTarget?.id else {
+            throw StringError("Unit test product '\(unitTestProduct.name)' is missing a PIF GUID")
+        }
+        self.project[keyPath: testRunnerTargetKeyPath].common.addDependency(
+            on: unitTestGUID,
+            platformFilters: [],
+            linkProduct: true
+        )
+
+        self.project[keyPath: testRunnerTargetKeyPath].common.addBuildConfig { id in
+            BuildConfig(
+                id: id,
+                name: "Debug",
+                settings: settings,
+                impartedBuildSettings: impartedSettings
+            )
+        }
+        self.project[keyPath: testRunnerTargetKeyPath].common.addBuildConfig { id in
+            BuildConfig(
+                id: id,
+                name: "Release",
+                settings: settings,
+                impartedBuildSettings: impartedSettings
+            )
+        }
+
+        let testRunner = PackagePIFBuilder.ModuleOrProduct(
+            type: .unitTestRunner,
+            name: name,
+            moduleName: moduleName,
+            pifTarget: .target(self.project[keyPath: testRunnerTargetKeyPath]),
+            indexableFileURLs: [],
+            headerFiles: [],
+            linkedPackageBinaries: [],
+            swiftLanguageVersion: nil,
+            declaredPlatforms: self.declaredPlatforms,
+            deploymentTargets: self.deploymentTargets
+        )
+        self.builtModulesAndProducts.append(testRunner)
+    }
 }
 
 // MARK: - Helper Types

Tests/CommandsTests/PackageCommandTests.swift

@@ -4106,11 +4106,12 @@ class PackageCommandSwiftBuildTests: PackageCommandTestCase {
         throw XCTSkip("SWBINTTODO: Build plan is not currently supported")
     }
 
+#if !os(macOS)
     override func testCommandPluginTestingCallbacks() async throws {
-        throw XCTSkip("SWBINTTODO: Requires PIF generation to adopt new test runner product type")
         try XCTSkipOnWindows(because: "TSCBasic/Path.swift:969: Assertion failed, https://github.com/swiftlang/swift-package-manager/issues/8602")
         try await super.testCommandPluginTestingCallbacks()
     }
+#endif
 
     override func testCommandPluginTargetBuilds() async throws {
         try XCTSkipOnWindows(because: "TSCBasic/Path.swift:969: Assertion failed, https://github.com/swiftlang/swift-package-manager/issues/8602")