Ensure short path names for generated tests on Windows, in test runner.

tools/testing/dart/test_suite.dart

Index: tools/testing/dart/test_suite.dart
diff --git a/tools/testing/dart/test_suite.dart b/tools/testing/dart/test_suite.dart
index ce30a7362eeb69ef33907a72bead29eae239b263..c73dc7c28841b77b49774be1b91550146699059b 100644
--- a/tools/testing/dart/test_suite.dart
+++ b/tools/testing/dart/test_suite.dart
@@ -2394,6 +2394,8 @@ class TestUtils {
   static List<String> getExtraVmOptions(Map configuration) =>
       getExtraOptions(configuration, 'vm_options');
 
+  static int shortNameCounter = 0;  // Make unique short file names on Windows.
+
   static String getShortName(String path) {
     final PATH_REPLACEMENTS = const {
       "pkg_polymer_e2e_test_bad_import_test": "polymer_bi",
@@ -2457,6 +2459,7 @@ class TestUtils {
     }
     path = path.replaceAll('/', '_');
     final int WINDOWS_SHORTEN_PATH_LIMIT = 58;
+    final int WINDOWS_PATH_END_LENGTH = 30;
     if (Platform.operatingSystem == 'windows' &&
         path.length > WINDOWS_SHORTEN_PATH_LIMIT) {
       for (var key in PATH_REPLACEMENTS.keys) {
@@ -2465,6 +2468,11 @@ class TestUtils {
           break;
         }
       }
+      if (path.length > WINDOWS_SHORTEN_PATH_LIMIT) {
+        ++shortNameCounter;
+        var pathEnd = path.substring(path.length - WINDOWS_PATH_END_LENGTH);
+        path = "short${shortNameCounter}_$pathEnd";

[Søren Gjesse, 2016/06/29 15:35:56]

Maybe add __ in front as well to lower the probability of a clash.

+      }
     }
     return path;
   }