Only allow one async operation on RandomAccessFile at a time.

tests/standalone/io/file_test.dart

Index: tests/standalone/io/file_test.dart
diff --git a/tests/standalone/io/file_test.dart b/tests/standalone/io/file_test.dart
index 3b8c383469b2f1d29ede4d03f6d3565e0c0ca285..d245bf6a6efe6452d1d26e72ff305c0e8a387dd8 100644
--- a/tests/standalone/io/file_test.dart
+++ b/tests/standalone/io/file_test.dart
@@ -1082,6 +1082,17 @@ class FileTest {
     });
   }
 
+  static void testDoubleAsyncRead() {

[Søren Gjesse, 2013/09/26 18:31:19]

testDoubleAsyncRead -> testDoubleAsyncOperation

[Anders Johnsen, 2013/10/01 10:50:40]

Done.

+    asyncTestStarted();
+    var file = new File(Platform.executable).openSync();
+    Future.wait([file.length(), file.length()])
+        .then((_) {
+          Expect.fail("should fail.");
+        }, onError: (_) {
+          asyncTestDone("testDoubleAsyncRead");
+        });
+  }
+
   static void testLastModifiedSync() {
     var modified = new File(Platform.executable).lastModifiedSync();
     Expect.isTrue(modified is DateTime);
@@ -1300,6 +1311,7 @@ class FileTest {
       testRename();
       testRenameSync();
       testLastModified();
+      testDoubleAsyncRead();
       asyncEnd();
     });
   }