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

tools/testing/dart/test_suite.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.
 
 /**
  * Classes and methods for enumerating and preparing tests.
  *
  * This library includes:
  *
  * - Creating tests by listing all the Dart files in certain directories,
@@ skipping 2376 matching lines @@
         .where((s) => s.isNotEmpty)
         .toList();
   }
 
   /**
    * Gets extra vm options passed to the testing script.
    */
   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",
       "pkg_polymer_e2e_test_canonicalization_test": "polymer_c16n",
       "pkg_polymer_e2e_test_experimental_boot_test": "polymer_boot",
       "pkg_polymer_e2e_test_good_import_test": "polymer_gi",
       "tests_co19_src_Language_12_Expressions_14_Function_Invocation_":
           "co19_fn_invoke_",
       "tests_co19_src_LayoutTests_fast_css_getComputedStyle_getComputedStyle-":
           "co19_css_getComputedStyle_",
@@ skipping 43 matching lines @@
     };
 
     // Some tests are already in [build_dir]/generated_tests.
     String GEN_TESTS = 'generated_tests/';
     if (path.contains(GEN_TESTS)) {
       int index = path.indexOf(GEN_TESTS) + GEN_TESTS.length;
       path = 'multitest/${path.substring(index)}';
     }
     path = path.replaceAll('/', '_');
     final int WINDOWS_SHORTEN_PATH_LIMIT = 58;
+    final int WINDOWS_PATH_END_LENGTH = 30;
     if (Platform.operatingSystem == 'windows' &&
         path.length > WINDOWS_SHORTEN_PATH_LIMIT) {
       for (var key in PATH_REPLACEMENTS.keys) {
         if (path.startsWith(key)) {
           path = path.replaceFirst(key, PATH_REPLACEMENTS[key]);
           break;
         }
       }
+      if (path.length > WINDOWS_SHORTEN_PATH_LIMIT) {
+        ++shortNameCounter;
+        var pathEnd = path.substring(path.length - WINDOWS_PATH_END_LENGTH);
+        path = "short${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;
   }
 }