Handle /dev/null on linux, as an closed device.

tests/standalone/io/dart_std_io_pipe_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // Test a dart sub-process handling stdio with different types of
 // redirection.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
@@ skipping 12 matching lines @@
 void checkFileContent(String fileName, String content) {
   RandomAccessFile pipeOut  = new File(fileName).openSync();
   int length = pipeOut.lengthSync();
   List data = new List<int>(length);
   pipeOut.readListSync(data, 0, length);
   Expect.equals(content, new String.fromCharCodes(data));
   pipeOut.closeSync();
 }
 
 
-void test(String shellScript, String dartScript, String type) {
+void test(String shellScript, String dartScript, String type, bool devNull) {
   Directory dir = new Directory("").createTempSync();
 
   // The shell script will run the dart executable passed with a
   // number of different redirections of stdio.
   String pipeOutFile = "${dir.path}/pipe";
+  if (devNull) pipeOutFile = "/dev/null";
   String redirectOutFile = "${dir.path}/redirect";
   String executable = new Options().executable;
   List args =
       [executable, dartScript, type, pipeOutFile, redirectOutFile];
   var future = Process.start(shellScript, args);
   future.then((process) {
     process.exitCode.then((exitCode) {
       Expect.equals(0, exitCode);
 
       // Check the expected file contents.
       if (type == "0") {
-        checkFileContent("${pipeOutFile}", "Hello\n");
+        if (devNull) {
+          checkFileEmpty("${redirectOutFile}.stdout");
+        } else {
+          checkFileContent("${pipeOutFile}", "Hello\n");
+          checkFileContent("${redirectOutFile}.stdout", "Hello\nHello\n");
+        }
         checkFileEmpty("${redirectOutFile}.stderr");
-        checkFileContent("${redirectOutFile}.stdout", "Hello\nHello\n");
       }
       if (type == "1") {
-        checkFileContent("${pipeOutFile}", "Hello\n");
+        if (devNull) {
+          checkFileEmpty("${redirectOutFile}.stderr");
+        } else {
+          checkFileContent("${pipeOutFile}", "Hello\n");
+          checkFileContent("${redirectOutFile}.stderr", "Hello\nHello\n");
+        }
         checkFileEmpty("${redirectOutFile}.stdout");
-        checkFileContent("${redirectOutFile}.stderr", "Hello\nHello\n");
       }
       if (type == "2") {
-        checkFileContent("${pipeOutFile}", "Hello\nHello\n");
-        checkFileContent("${redirectOutFile}.stdout",
-                         "Hello\nHello\nHello\nHello\n");
-        checkFileContent("${redirectOutFile}.stderr",
-                         "Hello\nHello\nHello\nHello\n");
+        if (devNull) {
+          checkFileEmpty("${redirectOutFile}.stdout");
+          checkFileEmpty("${redirectOutFile}.stderr");
+        } else {
+          checkFileContent("${pipeOutFile}", "Hello\nHello\n");
+          checkFileContent("${redirectOutFile}.stdout",
+                           "Hello\nHello\nHello\nHello\n");
+          checkFileContent("${redirectOutFile}.stderr",
+                           "Hello\nHello\nHello\nHello\n");
+        }
       }
 
       // Cleanup test directory.
       dir.deleteSync(recursive: true);
     });
     // Drain out and err streams so they close.
     process.stdout.listen((_) {});
     process.stderr.listen((_) {});
   });
   future.catchError((error) {
@@ skipping 15 matching lines @@
   if (!shellScript.existsSync()) {
     shellScript = new File("../tests/standalone/io/dart_std_io_pipe_test.sh");
   }
   // Get the Dart script file which echoes stdin to stdout or stderr or both.
   var scriptFile = new File("tests/standalone/io/process_std_io_script.dart");
   if (!scriptFile.existsSync()) {
     scriptFile = new File("../tests/standalone/io/process_std_io_script.dart");
   }
 
   // Run the shell script.
-  test(shellScript.path, scriptFile.path, "0");
-  test(shellScript.path, scriptFile.path, "1");
-  test(shellScript.path, scriptFile.path, "2");
+  test(shellScript.path, scriptFile.path, "0", false);
+  test(shellScript.path, scriptFile.path, "0", true);
+  test(shellScript.path, scriptFile.path, "1", false);
+  test(shellScript.path, scriptFile.path, "1", true);
+  test(shellScript.path, scriptFile.path, "2", false);
+  test(shellScript.path, scriptFile.path, "2", true);
 }