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 +1,62 @@
+// 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";
+
+var coverageToolUrl = "tools/coverage.dart";
+var coverageTargetUrl = "tests/language/hello_dart_test.dart";

[kustermann, 2013/05/31 13:41:28]

Using paths relative to dart/ requires this script to be always called from
within dart/. It's ok, but you could get the path to this script using 'new
Options().script' and navigate up.

[kustermann, 2013/05/31 13:41:28]

These are not really urls. You could rename them to 'coverageToolPath' or so.

[hausner, 2013/05/31 21:53:02]

Done.

[hausner, 2013/05/31 21:53:02]

Changed to use paths relative to the path of this script. I could not find a way
to get to the absolute path of the root of the dart tree. 

+Process coverageToolProcess;
+List sourceLines;
+int nextLineToMatch = 0;
+
+void onCoverageOutput(String line) {
+  print("COV: $line");
+  if (nextLineToMatch < sourceLines.length) {
+    if (line.endsWith(sourceLines[nextLineToMatch])) {
+      nextLineToMatch++;

[kustermann, 2013/05/31 13:41:28]

If I see this correct, you actually don't verify the output of the coverage
tool. You only check that the source code of 'hello_dart_test.dart' is contained
in the output.
Is this what you want to do? If so, I'm fine with it.

[hausner, 2013/05/31 21:53:02]

Correct. I just want to make sure the coverage tool compiles and runs. I am not
interested in checking a specific coverage counter. By checking that the
coverage tool prints out the source it inspected, I assume the coverage tool ran
fine.

+    }
+  }
+}
+
+void onCoverageExit(exitCode) {
+  var pid = coverageToolProcess.pid;
+  print("process $pid terminated with exit code $exitCode.");
+  if (nextLineToMatch < sourceLines.length) {
+    print("Error: could not match all source code lines "
+          "of '$coverageTargetUrl'");
+    exit(-1);
+  } else {
+    print("Successfully matched all lines of '$coverageTargetUrl'");
+  }
+}
+
+void main() {
+  var options = new Options();
+  var targetOpts = [ "--compile_all", coverageToolUrl, coverageTargetUrl ];
+
+  sourceLines = new File(Uri.parse(coverageTargetUrl).path).readAsLinesSync();

[kustermann, 2013/05/31 13:41:28]

Uri.path will give you always forward slashes AFAIK. You could use
'new Path(coverageTargetUrl).toNativePath()'.

[hausner, 2013/05/31 21:53:02]

Done.

+  assert(sourceLines != null);
+
+  Process.start(options.executable, targetOpts).then((Process process) {

[ricow1, 2013/05/31 05:29:02]

No need to use Process.start here, use Process.run instead, will simplify this a
lot

[kustermann, 2013/05/31 13:41:28]

agreed.

[hausner, 2013/05/31 21:53:02]

I don't know how I'd get to stdout and stderr of the child process if I use
run(). If you feel strongly i will do this in a later checkin.

[ricow1, 2013/06/01 06:27:58]

Process.run(bin, args).then((result) {
  print(result.stderr);
  print(result.stdout);
  print(result.exitCode);
  print(result.pid);
});

+    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);
+  });
+}