Add coverage tool to standalone tests

tests/standalone/coverage_test.dart

Index: tests/standalone/coverage_test.dart
===================================================================
--- tests/standalone/coverage_test.dart	(revision 0)
+++ tests/standalone/coverage_test.dart	(revision 0)
@@ -0,0 +1,75 @@
+// Copyright (c) 2013, 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.
+
+// This test forks a second vm process that runs the script tools/coverage.dart
+// and verifies that the coverage tool produces its expected output.
+// This test is mainly here to ensure that the coverage tool compiles and
+// runs.
+
+import "dart:io";
+import "dart:utf";
+
+// Coverage tool script relative to the path of this test.
+var coverageToolScript = "../../tools/coverage.dart";
+
+// Coverage target script relative to this test.
+var coverageTargetScript = "../language/hello_dart_test.dart";
+var targPath;
+
+Process coverageToolProcess;
+List sourceLines;
+int nextLineToMatch = 0;
+
+void onCoverageOutput(String line) {
+  print("COV: $line");
+  if (nextLineToMatch < sourceLines.length) {
+    if (line.endsWith(sourceLines[nextLineToMatch])) {
+      nextLineToMatch++;
+    }
+  }
+}
+
+void onCoverageExit(exitCode) {
+  var pid = coverageToolProcess.pid;
+  print("process $pid terminated with exit code $exitCode.");
+  if (nextLineToMatch < sourceLines.length) {
+    print("Error: could not match all source code lines of '$targPath'");
+    exit(-1);
+  } else {
+    print("Successfully matched all lines of '$targPath'");
+  }
+}
+
+void main() {
+  var options = new Options();
+
+  // Compute paths for coverage tool and coverage target relative
+  // the the path of this script.
+  var scriptPath = new Path(options.script).directoryPath;
+  var toolPath = scriptPath.join(new Path(coverageToolScript)).canonicalize();
+  targPath = scriptPath.join(new Path(coverageTargetScript)).canonicalize();
+
+  sourceLines = new File(targPath.toNativePath()).readAsLinesSync();
+  assert(sourceLines != null);
+
+  var processOpts = [ "--compile_all",
+                      toolPath.toNativePath(),
+                      targPath.toNativePath() ];
+
+  Process.start(options.executable, processOpts).then((Process process) {
+    coverageToolProcess = process;
+    coverageToolProcess.stdin.close();
+    var stdoutStringStream = coverageToolProcess.stdout
+        .transform(new StringDecoder())
+        .transform(new LineTransformer());
+    stdoutStringStream.listen(onCoverageOutput);
+
+    var stderrStringStream = coverageToolProcess.stderr
+        .transform(new StringDecoder())
+        .transform(new LineTransformer());
+    stderrStringStream.listen(onCoverageOutput);
+
+    coverageToolProcess.exitCode.then(onCoverageExit);
+  });
+}