Tests: Conditionally skip the Archiver tests

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

Author: bkhouri

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

@@ -18,6 +18,15 @@ import XCTest
 import struct TSCBasic.FileSystemError
 
 final class TarArchiverTests: XCTestCase {
+    override func setUp() async throws {
+        #if os(Windows)
+            let requiredProcess = "tar.exe"
+        #else
+            let requiredProcess = "tar"
+        #endif
+        try XCTRequires(executable: requiredProcess)
+    }
+
     func testSuccess() async throws {
         try await testWithTemporaryDirectory { tmpdir in
             let archiver = TarArchiver(fileSystem: localFileSystem)

Tests/BasicsTests/Archiver/UniversalArchiverTests.swift

@@ -18,6 +18,18 @@ import XCTest
 import struct TSCBasic.FileSystemError
 
 final class UniversalArchiverTests: XCTestCase {
+    override func setUp() async throws {
+        #if os(Windows)
+            let requiredTarProcess = "tar.exe"
+            let requiredZipProcess = "zip.exe"
+        #else
+            let requiredTarProcess = "tar"
+            let requiredZipProcess = "zip"
+        #endif
+        try XCTRequires(executable: requiredTarProcess)
+        try XCTRequires(executable: requiredZipProcess)
+    }
+
     func testSuccess() async throws {
         try await testWithTemporaryDirectory { tmpdir in
             let archiver = UniversalArchiver(localFileSystem)

Tests/BasicsTests/Archiver/ZipArchiverTests.swift

@@ -18,6 +18,15 @@ import TSCclibc // for SPM_posix_spawn_file_actions_addchdir_np_supported
 import struct TSCBasic.FileSystemError
 
 final class ZipArchiverTests: XCTestCase {
+    override func setUp() async throws {
+        #if os(Windows)
+            let requiredProcess = "zip.exe"
+        #else
+            let requiredProcess = "zip"
+        #endif
+        try XCTRequires(executable: requiredProcess)
+    }
+
     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