TestFoundation: remove mkstemp usage

`mkstemp` is not available on Windows.  Replace the two sites with a
GUID temporary path instead.

Author: compnerd

TestFoundation/TestFileHandle.swift

@@ -280,39 +280,42 @@ class TestFileHandle : XCTestCase {
         XCTAssertEqual(fh.readDataToEndOfFile().count, 0)
     }
 
-    func test_truncateFile() {
-        mkstemp(template: "test_truncateFile.XXXXXX") { (fh) in
-            fh.truncateFile(atOffset: 50)
-            XCTAssertEqual(fh.offsetInFile, 50)
+    func test_truncateFile() throws {
+        let url: URL = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(ProcessInfo.processInfo.globallyUniqueString)
+        try FileManager.default.createDirectory(at: url, withIntermediateDirectories: true)
 
-            fh.truncateFile(atOffset: 0)
-            XCTAssertEqual(fh.offsetInFile, 0)
+        let fh: FileHandle = try FileHandle(forWritingTo: url)
 
-            fh.truncateFile(atOffset: 100)
-            XCTAssertEqual(fh.offsetInFile, 100)
+        fh.truncateFile(atOffset: 50)
+        XCTAssertEqual(fh.offsetInFile, 50)
 
-            fh.write(Data([1, 2]))
-            XCTAssertEqual(fh.offsetInFile, 102)
+        fh.truncateFile(atOffset: 0)
+        XCTAssertEqual(fh.offsetInFile, 0)
 
-            fh.seek(toFileOffset: 4)
-            XCTAssertEqual(fh.offsetInFile, 4)
+        fh.truncateFile(atOffset: 100)
+        XCTAssertEqual(fh.offsetInFile, 100)
 
-            (0..<20).forEach { fh.write(Data([$0])) }
-            XCTAssertEqual(fh.offsetInFile, 24)
+        fh.write(Data([1, 2]))
+        XCTAssertEqual(fh.offsetInFile, 102)
 
-            fh.seekToEndOfFile()
-            XCTAssertEqual(fh.offsetInFile, 102)
+        fh.seek(toFileOffset: 4)
+        XCTAssertEqual(fh.offsetInFile, 4)
 
-            fh.truncateFile(atOffset: 10)
-            XCTAssertEqual(fh.offsetInFile, 10)
+        (0..<20).forEach { fh.write(Data([$0])) }
+        XCTAssertEqual(fh.offsetInFile, 24)
 
-            fh.seek(toFileOffset: 0)
-            XCTAssertEqual(fh.offsetInFile, 0)
+        fh.seekToEndOfFile()
+        XCTAssertEqual(fh.offsetInFile, 102)
 
-            let data = fh.readDataToEndOfFile()
-            XCTAssertEqual(data.count, 10)
-            XCTAssertEqual(data, Data([0, 0, 0, 0, 0, 1, 2, 3, 4, 5]))
-        }
+        fh.truncateFile(atOffset: 10)
+        XCTAssertEqual(fh.offsetInFile, 10)
+
+        fh.seek(toFileOffset: 0)
+        XCTAssertEqual(fh.offsetInFile, 0)
+
+        let data = fh.readDataToEndOfFile()
+        XCTAssertEqual(data.count, 10)
+        XCTAssertEqual(data, Data([0, 0, 0, 0, 0, 1, 2, 3, 4, 5]))
     }
 
     func test_readabilityHandlerCloseFileRace() throws {

TestFoundation/TestProcess.swift

@@ -225,27 +225,30 @@ class TestProcess : XCTestCase {
         XCTAssertEqual(errMsg, "cat: invalid_file_name: No such file or directory\n")
     }
 
-    func test_file_stdout() {
+    func test_file_stdout() throws {
         let process = Process()
 
         process.launchPath = "/usr/bin/which"
         process.arguments = ["which"]
 
-        mkstemp(template: "TestProcess.XXXXXX") { handle in
-            process.standardOutput = handle
+        let url: URL = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(ProcessInfo.processInfo.globallyUniqueString)
+        try FileManager.default.createDirectory(at: url, withIntermediateDirectories: true)
 
-            process.launch()
-            process.waitUntilExit()
-            XCTAssertEqual(process.terminationStatus, 0)
+        let handle: FileHandle = try FileHandle(forWritingTo: url)
 
-            handle.seek(toFileOffset: 0)
-            let data = handle.readDataToEndOfFile()
-            guard let string = String(data: data, encoding: .ascii) else {
-                XCTFail("Could not read stdout")
-                return
-            }
-            XCTAssertTrue(string.hasSuffix("/which\n"))
+        process.standardOutput = handle
+
+        process.launch()
+        process.waitUntilExit()
+        XCTAssertEqual(process.terminationStatus, 0)
+
+        handle.seek(toFileOffset: 0)
+        let data = handle.readDataToEndOfFile()
+        guard let string = String(data: data, encoding: .ascii) else {
+            XCTFail("Could not read stdout")
+            return
         }
+        XCTAssertTrue(string.hasSuffix("/which\n"))
     }
 
     func test_passthrough_environment() {

TestFoundation/TestUtils.swift

@@ -42,16 +42,3 @@ func ensureFiles(_ fileNames: [String]) -> Bool {
     }
     return result
 }
-
-func mkstemp(template: String, body: (FileHandle) throws -> Void) rethrows {
-    let url = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(template)
-
-    try url.withUnsafeFileSystemRepresentation {
-        switch mkstemp(UnsafeMutablePointer(mutating: $0!)) {
-        case -1: XCTFail("Could not create temporary file")
-        case let fd:
-            defer { url.withUnsafeFileSystemRepresentation { _ = unlink($0!) } }
-            try body(FileHandle(fileDescriptor: fd, closeOnDealloc: true))
-        }
-    }
-}