Ensure attachments path directory is created

Sources/Testing/ABI/EntryPoints/EntryPoint.swift

@@ -8,6 +8,9 @@
 // See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 //
 
+#if canImport(Foundation)
+private import Foundation
+#endif
 private import _TestingInternals
 
 #if canImport(Synchronization)
@@ -622,9 +625,14 @@ public func configurationForEntryPoint(from args: __CommandLineArguments_v0) thr
 
   // Attachment output.
   if let attachmentsPath = args.attachmentsPath {
-    guard fileExists(atPath: attachmentsPath) else {
-      throw _EntryPointError.invalidArgument("---attachments-path", value: attachmentsPath)
-    }
+
+    #if canImport(Foundation)
+      try FileManager().createDirectory(atPath: attachmentsPath, withIntermediateDirectories: true)
+    #else
+      guard fileExists(atPath: attachmentsPath) else {
+        throw _EntryPointError.invalidArgument("---attachments-path", value: attachmentsPath)
+      }
+    #endif
     configuration.attachmentsPath = attachmentsPath
   }
 

Sources/Testing/Testing.docc/Attachments.md

@@ -244,8 +244,8 @@ after your tests finish running:
   `.build/attachments` by default. Visual Studio Code reports the paths to
   individual attachments in its Tests Results panel.
 - When using Swift Package Manager's `swift test` command, you can pass the
-  `--attachments-path` option. The testing library saves attachments to the
-  specified directory.
+  `--attachments-path` option. The testing library creates a directory at the
+  specified path and saves attachments to it.
 
   If you do not pass the `--attachments-path` option, the testing library does
   not save any attachments you record.

Tests/TestingTests/SwiftPMTests.swift

@@ -10,6 +10,9 @@
 
 @testable @_spi(Experimental) @_spi(ForToolsIntegrationOnly) import Testing
 private import _TestingInternals
+#if canImport(Foundation)
+private import Foundation
+#endif
 
 private func configurationForEntryPoint(withArguments args: [String]) throws -> Configuration {
   let args = try parseCommandLineArguments(from: args)
@@ -385,6 +388,57 @@ struct SwiftPMTests {
     #expect(fileContents.contains(UInt8(ascii: ">")))
   }
 
+  #if canImport(Foundation)
+  @Test(
+    "--attachments-path argument (creates missing directory)",
+    arguments: ["--attachments-path", "--experimental-attachments-path"]
+  )
+  func attachmentsPathCreatesMissingDirectory(argumentName: String) throws {
+      let tempDirPath = try temporaryDirectory()
+      let attachmentsPath = appendPathComponent("swt_attachments_\(UInt64.random(in: 0 ..< .max))", to: tempDirPath)
+      defer {
+        _ = remove(attachmentsPath)
+      }
+      #expect(!fileExists(atPath: attachmentsPath))
+      let configuration = try configurationForEntryPoint(withArguments: ["PATH", argumentName, attachmentsPath])
+      #expect(fileExists(atPath: attachmentsPath))
+      let actualPath = try #require(configuration.attachmentsPath, "Attachments path is not expected to be nil")
+      #expect(canonicalizePath(actualPath) == canonicalizePath(attachmentsPath))
+  }
+  #endif
+
+  #if canImport(Foundation)
+  @Test("--attachments-path argument (bad path)")
+  func attachmentsPathWithBadPath() throws {
+      let tempDirPath = try temporaryDirectory()
+      let attachmentPath = appendPathComponent(UUID().uuidString, to: tempDirPath)
+      let fileManager = FileManager()
+      let success = fileManager.createFile(atPath: attachmentPath, contents: nil, )
+      if !success {
+        Issue.record("Test setup failure.  Could not create file at \(attachmentPath).")
+      }
+      defer {
+        print("removing \(attachmentPath) ...")
+        _ = remove(attachmentPath)
+      }
+      #expect(throws: (any Error).self, "Attachment path is: \(attachmentPath)") {
+        _ = try configurationForEntryPoint(withArguments: ["PATH", "--attachments-path", attachmentPath])
+      }
+  }
+  #endif
+
+  @Test("--attachments-path argument (accepts existing directory)")
+  func attachmentsPathAcceptsExistingDirectory() throws {
+    let tempDirPath = try temporaryDirectory()
+    #expect(fileExists(atPath: tempDirPath))
+    let configuration = try configurationForEntryPoint(withArguments: ["PATH", "--attachments-path", tempDirPath])
+    let actualPath = try #require(configuration.attachmentsPath, "Attachments path is not expected to be nil")
+    #expect(
+      canonicalizePath(actualPath) == canonicalizePath(tempDirPath),
+      "Canonicalized actual path (\(actualPath)) is not equal to canonicalized expected path (\(tempDirPath))",
+    )
+  }
+
   @Test("--configuration-path argument", arguments: [
     "--configuration-path", "--experimental-configuration-path",
   ])