Tests: Conditionally skip the Archiver tests (#8601)

The Archiver tests has a dependency on a system binary being available
on the host. Update the archiver test to skip the test is the required
executable is not available on the system.

Fixes: #8586
Issue: rdar://150414402
Required for: swiftlang/swift#80405

Author: bkhouri

Sources/Basics/Archiver/TarArchiver.swift

@@ -25,7 +25,7 @@ public struct TarArchiver: Archiver {
     private let cancellator: Cancellator
 
     /// The underlying command
-    private let tarCommand: String
+    internal let tarCommand: String
 
     /// Creates a `TarArchiver`.
     ///

Sources/Basics/Archiver/ZipArchiver.swift

@@ -29,7 +29,14 @@ public struct ZipArchiver: Archiver, Cancellable {
 
     /// Absolute path to the Windows tar in the system folder
     #if os(Windows)
-    private let windowsTar: String
+        internal let windowsTar: String
+    #else
+        internal let unzip = "unzip"
+        internal let zip = "zip"
+    #endif
+
+    #if os(FreeBSD)
+        internal let tar = "tar"
     #endif
 
     /// Creates a `ZipArchiver`.
@@ -74,7 +81,9 @@ public struct ZipArchiver: Archiver, Cancellable {
             // It's part of system32 anyway so use the absolute path.
             let process = AsyncProcess(arguments: [windowsTar, "xf", archivePath.pathString, "-C", destinationPath.pathString])
             #else
-            let process = AsyncProcess(arguments: ["unzip", archivePath.pathString, "-d", destinationPath.pathString])
+                let process = AsyncProcess(arguments: [
+                    self.unzip, archivePath.pathString, "-d", destinationPath.pathString,
+                ])
             #endif
             guard let registrationKey = self.cancellator.register(process) else {
                 throw CancellationError.failedToRegisterProcess(process)
@@ -113,7 +122,10 @@ public struct ZipArchiver: Archiver, Cancellable {
         // On FreeBSD, the unzip command is available in base but not the zip command.
         // Therefore; we use libarchive(bsdtar) to produce the ZIP archive instead.
         let process = AsyncProcess(
-          arguments: ["tar", "-c", "--format", "zip", "-f", destinationPath.pathString, directory.basename],
+                arguments: [
+                    self.tar, "-c", "--format", "zip", "-f", destinationPath.pathString,
+                    directory.basename,
+                ],
           workingDirectory: directory.parentDirectory
         )
         #else
@@ -127,7 +139,7 @@ public struct ZipArchiver: Archiver, Cancellable {
             arguments: [
                 "/bin/sh",
                 "-c",
-                "cd \(directory.parentDirectory.underlying.pathString) && zip -ry \(destinationPath.pathString) \(directory.basename)",
+                    "cd \(directory.parentDirectory.underlying.pathString) && \(self.zip) -ry \(destinationPath.pathString) \(directory.basename)"
             ]
         )
         #endif
@@ -154,7 +166,7 @@ public struct ZipArchiver: Archiver, Cancellable {
             #if os(Windows)
             let process = AsyncProcess(arguments: [windowsTar, "tf", path.pathString])
             #else
-            let process = AsyncProcess(arguments: ["unzip", "-t", path.pathString])
+                let process = AsyncProcess(arguments: [self.unzip, "-t", path.pathString])
             #endif
             guard let registrationKey = self.cancellator.register(process) else {
                 throw CancellationError.failedToRegisterProcess(process)

Sources/_InternalTestSupport/XCTAssertHelpers.swift

@@ -76,6 +76,31 @@ public func XCTSkipOnWindows(because reason: String? = nil, skipPlatformCi: Bool
     #endif
 }
 
+public func _requiresTools(_ executable: String) throws {
+    func getAsyncProcessArgs(_ executable: String) -> [String] {
+        #if os(Windows)
+            let args = ["cmd.exe", "/c", "where.exe", executable]
+        #else
+            let args = ["which", executable]
+        #endif
+        return args
+    }
+    try AsyncProcess.checkNonZeroExit(arguments: getAsyncProcessArgs(executable))
+}
+public func XCTRequires(
+    executable: String,
+    file: StaticString = #filePath,
+    line: UInt = #line
+) throws {
+
+    do {
+        try _requiresTools(executable)
+    } catch (let AsyncProcessResult.Error.nonZeroExit(result)) {
+        throw XCTSkip(
+            "Skipping as tool \(executable) is not found in the path. (\(result.description))")
+    }
+}
+
 /// An `async`-friendly replacement for `XCTAssertThrowsError`.
 public func XCTAssertAsyncThrowsError<T>(
     _ expression: @autoclosure () async throws -> T,

Tests/BasicsTests/Archiver/TarArchiverTests.swift

@@ -11,13 +11,19 @@
 //===----------------------------------------------------------------------===//
 
 import Basics
+@testable import struct Basics.TarArchiver
 import TSCclibc // for SPM_posix_spawn_file_actions_addchdir_np_supported
 import _InternalTestSupport
 import XCTest
 
 import struct TSCBasic.FileSystemError
 
 final class TarArchiverTests: XCTestCase {
+    override func setUp() async throws {
+        let archiver = TarArchiver(fileSystem: localFileSystem)
+        try XCTRequires(executable: archiver.tarCommand)
+    }
+
     func testSuccess() async throws {
         try await testWithTemporaryDirectory { tmpdir in
             let archiver = TarArchiver(fileSystem: localFileSystem)

Tests/BasicsTests/Archiver/UniversalArchiverTests.swift

@@ -11,13 +11,31 @@
 //===----------------------------------------------------------------------===//
 
 import Basics
+@testable import struct Basics.TarArchiver
+@testable import struct Basics.ZipArchiver
 import TSCclibc // for SPM_posix_spawn_file_actions_addchdir_np_supported
 import _InternalTestSupport
 import XCTest
 
 import struct TSCBasic.FileSystemError
 
 final class UniversalArchiverTests: XCTestCase {
+    override func setUp() async throws {
+        let zipAchiver = ZipArchiver(fileSystem: localFileSystem)
+        #if os(Windows)
+            try XCTRequires(executable: zipAchiver.windowsTar)
+        #else
+            try XCTRequires(executable: zipAchiver.unzip)
+            try XCTRequires(executable: zipAchiver.zip)
+        #endif
+        #if os(FreeBSD)
+            try XCTRequires(executable: zipAchiver.tar)
+        #endif
+
+        let tarAchiver = TarArchiver(fileSystem: localFileSystem)
+        try XCTRequires(executable: tarAchiver.tarCommand)
+    }
+
     func testSuccess() async throws {
         try await testWithTemporaryDirectory { tmpdir in
             let archiver = UniversalArchiver(localFileSystem)

Tests/BasicsTests/Archiver/ZipArchiverTests.swift

@@ -11,13 +11,27 @@
 //===----------------------------------------------------------------------===//
 
 import Basics
+@testable import struct Basics.ZipArchiver
 import _InternalTestSupport
 import XCTest
 import TSCclibc // for SPM_posix_spawn_file_actions_addchdir_np_supported
 
 import struct TSCBasic.FileSystemError
 
 final class ZipArchiverTests: XCTestCase {
+    override func setUp() async throws {
+        let archiver = ZipArchiver(fileSystem: localFileSystem)
+        #if os(Windows)
+            try XCTRequires(executable: archiver.windowsTar)
+        #else
+            try XCTRequires(executable: archiver.unzip)
+            try XCTRequires(executable: archiver.zip)
+        #endif
+        #if os(FreeBSD)
+            try XCTRequires(executable: archiver.tar)
+        #endif
+    }
+
     func testZipArchiverSuccess() async throws {
         try await testWithTemporaryDirectory { tmpdir in
             let archiver = ZipArchiver(fileSystem: localFileSystem)

Tests/_InternalTestSupportTests/Misc.swift

@@ -1,3 +1,14 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2024-2025 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 SPMBuildCore
 import _InternalTestSupport
 import XCTest

Tests/_InternalTestSupportTests/XCTAssertHelpersTests.swift

@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 Basics
+import XCTest
+import func _InternalTestSupport.XCTAssertThrows
+import func _InternalTestSupport._requiresTools
+
+final class TestRequiresTool: XCTestCase {
+    func testErrorIsThrownIfExecutableIsNotFoundOnThePath() throws {
+        XCTAssertThrows(
+            try _requiresTools("doesNotExists")
+        ) { (error: AsyncProcessResult.Error) in
+            return true
+        }
+    }
+
+    func testErrorIsNotThrownIfExecutableIsOnThePath() throws {
+        // Essentially call either "which which" or "where.exe where.exe"
+        #if os(Window)
+        let executable = "where.exe"
+        #else
+        let executable = "which"
+        #endif
+        XCTAssertNoThrow(
+            try _requiresTools(executable)
+        )
+    }
+}