Modify tests to use Directory.systemTemp

tests/standalone/io/file_non_ascii_test.dart

Index: tests/standalone/io/file_non_ascii_test.dart
diff --git a/tests/standalone/io/file_non_ascii_test.dart b/tests/standalone/io/file_non_ascii_test.dart
index a64beee641bd57c6a39eb95e11817e278a335718..3a3c85dc18682d48bd7080b990ea6b5fe91637ea 100644
--- a/tests/standalone/io/file_non_ascii_test.dart
+++ b/tests/standalone/io/file_non_ascii_test.dart
@@ -15,31 +15,31 @@ main() {
   var precomposed = 'æøå';
   var decomposed = new String.fromCharCodes([47, 230, 248, 97, 778]);
 
-  new Directory('').createTemp().then((tempDir) {
-      Directory nonAsciiDir = new Directory('${tempDir.path}/æøå');
-      nonAsciiDir.create().then((nonAsciiDir) {
-        nonAsciiDir.exists().then((result) {
-          Expect.isTrue(result);
-          File nonAsciiFile = new File('${nonAsciiDir.path}/æøå.txt');
-          nonAsciiFile.writeAsString('æøå').then((_) {
-            nonAsciiFile.exists().then((result) {
-              Expect.isTrue(result);
-              nonAsciiFile.readAsString().then((contents) {
-                // The contents of the file is precomposed utf8.
-                Expect.equals(precomposed, contents);
-                nonAsciiFile.create().then((_) {
-                  var d = nonAsciiFile.directory;
-                  Expect.isTrue(d.path.endsWith(precomposed) ||
-                                d.path.endsWith(decomposed));
-                  nonAsciiFile.length().then((length) {
-                    Expect.equals(6, length);
-                    nonAsciiFile.lastModified().then((_) {
-                      nonAsciiFile.fullPath().then((path) {
-                        Expect.isTrue(path.endsWith('${precomposed}.txt') ||
-                                      path.endsWith('${decomposed}.txt'));
-                        tempDir.delete(recursive: true).then((_) {
+  Directory.systemTemp.createTemp('dart_file_non_ascii').then((tempDir) {
+    Directory nonAsciiDir = new Directory('${tempDir.path}/æøå');
+    nonAsciiDir.create().then((nonAsciiDir) {
+      nonAsciiDir.exists().then((result) {
+        Expect.isTrue(result);
+        File nonAsciiFile = new File('${nonAsciiDir.path}/æøå.txt');
+        nonAsciiFile.writeAsString('æøå').then((_) {
+          nonAsciiFile.exists().then((result) {
+            Expect.isTrue(result);
+            nonAsciiFile.readAsString().then((contents) {
+              // The contents of the file is precomposed utf8.
+              Expect.equals(precomposed, contents);
+              nonAsciiFile.create().then((_) {
+                var d = nonAsciiFile.directory;
+                Expect.isTrue(d.path.endsWith(precomposed) ||
+                              d.path.endsWith(decomposed));
+                nonAsciiFile.length().then((length) {
+                  Expect.equals(6, length);
+                  nonAsciiFile.lastModified().then((_) {
+                    nonAsciiFile.fullPath().then((path) {
+                      Expect.isTrue(path.endsWith('${precomposed}.txt') ||
+                                    path.endsWith('${decomposed}.txt'));
+                      tempDir.delete(recursive: true).then((_) {
                         asyncEnd();
-                      });
+                        });
                     });
                   });
                 });