Add debugging output to full_coverage_test to help diagnose timeouts.

tests/standalone/full_coverage_test.dart

 // Copyright (c) 2014, 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.
 
 // These tests fork a second VM process that runs the script
 // ``tools/full-coverage.dart'' and verifies that the tool
 // produces the expeced output.
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
 import 'package:path/path.dart' as path;
 import 'package:unittest/unittest.dart';
 
 final String coverageScript =
     Platform.script.resolve('../../tools/full-coverage.dart').toFilePath();
 final String packageRoot = Platform.packageRoot;
 final List dartBaseArgs = ['--package-root=${packageRoot}', '--checked',];
+final Stopwatch sw = new Stopwatch();
+
+int elapsed() => sw.elapsedMilliseconds;
 
 // With line numbers starting at 0, the list of hits can be understood as
 // follows:
 // * -1: No coverage data on this line.
 // *  0: No hits on this line.
 // *  1: ``Some'' hits on this line.
 final coverageTests = [
   {
     'name': 'faculty',
     'program': '''
@@ skipping 51 matching lines @@
   }
   return testDir.path;
 }
 
 
 destroyEnv(base) => new Directory(base).deleteSync(recursive: true);
 
 
 generateCoverage(String workingDirectory) {
   for (var coverageProg in coverageTests) {
+    print('[+${elapsed()}ms] Generating data for ${coverageProg["name"]}');
     var progPath = path.join(workingDirectory, coverageProg['name']);
     var script = path.join(progPath, "${coverageProg['name']}.dart");
     var dartArgs = new List.from(dartBaseArgs)
       ..addAll(['--coverage-dir=${progPath}', '${script}']);
     var result = Process.runSync(Platform.executable, dartArgs);
     if (result.exitCode != 0) {
-      print("Coverage generator returned exitCode: ${result.exitCode}.");
+      print("[+${elapsed()}ms] Got exitCode: ${result.exitCode}.");
       print("stderr:\n${result.stderr}\n");
       expect(result.exitCode, 0);
     }
   }
 }
 
 
 Future<Process> convertCoverage(String programDir, String format) {
   var dartArgs = new List.from(dartBaseArgs)
       ..addAll([
@@ skipping 97 matching lines @@
       // Make sure that there are only lines left that do not contain coverage
       // data.
       expectedHitMap.forEach((e) => expect(e, -1));
     }), completes);
   }), completes);
 }
 
 
 main() {
   String testingDirectory;
+  sw.start();
 
   setUp(() {
     testingDirectory = prepareEnv();
   });
 
   tearDown(() => destroyEnv(testingDirectory));
 
   test('CoverageTests', () {
-    print('Generating coverage data...');
+    print('[+${elapsed()}ms] Generating coverage data...');
     generateCoverage(testingDirectory);
-    print('Done Generating coverage data.');
+    print('[+${elapsed()}ms] Done Generating coverage data.');
 
-    print('Running tests...');
+    print('[+${elapsed()}ms] Running tests...');
     coverageTests.forEach((cTest) {
       String programDir = path.join(testingDirectory, cTest['name']);
       String programPath = path.join(programDir, "${cTest['name']}.dart");
+      print('[+${elapsed()}ms] Testing lcov for ${cTest["name"]}');
       testCoverage(programDir, programPath,
                    new LcovDescriptor(programPath),
                    new List.from(cTest['expectedHits']));
+      print('[+${elapsed()}ms] Testing pretty print for ${cTest["name"]}');
       testCoverage(programDir, programPath,
                    new PrettyPrintDescriptor(programPath),
                    new List.from(cTest['expectedHits']));
     });
+    print('[+${elapsed()}ms] Done.');
   });
 }