Unit test improvements.

pkg/unittest/lib/unittest.dart

Index: pkg/unittest/lib/unittest.dart
===================================================================
--- pkg/unittest/lib/unittest.dart	(revision 22128)
+++ pkg/unittest/lib/unittest.dart	(working copy)
@@ -181,8 +181,17 @@
 
 Configuration _config;
 
-/** [Configuration] used by the unittest library. */
-Configuration get unittestConfiguration => _config;
+/**
+ * [Configuration] used by the unittest library. Note that if a 
+ * configuration has not been set, calling this getter will create
+ * a default configuration.
+ */
+Configuration get unittestConfiguration {
+  if (_config == null) {
+    _config = new Configuration();
+  }
+  return _config;
+}
 
 /**
  * Sets the [Configuration] used by the unittest library.
@@ -859,3 +868,69 @@
 
 /** Signature for a test function. */
 typedef dynamic TestFunction();
+
+// Stack formatting utility. Strips extraneous content from a stack trace.
+// Stack fram lines are parsed with a regexp, which has been tested

[Siggi Cherem (dart-lang), 2013/04/30 00:42:33]

fram => frame

[gram, 2013/04/30 01:00:09]

Done.

+// in Chrome, Firefox and the VM. If a line fails to be parsed it is 
+// included in the output to be conservative.
+//
+// The output stack consists of everything after the call to TestCase._run.
+// If we see an 'expect' in the frame we will prune everything above that
+// as well.
+final _frameRegExp = new RegExp(
+    r'^\s*(?:(?:#\d+\s*)|(?:at )|(?:))(.+)\s*[@\(]((?:.+:\/\/.+\/[^:]*)|(?:dart:[^:]*)|(?:package:[^:]*)):([:\d]+)[\)]?$');

[Siggi Cherem (dart-lang), 2013/04/30 00:42:33]

is there a way to split this string in pieces to make it easier to understand?
new RegExp(
  r'^\s*'  // spaces
  r'(?:(?:#\d+\s*)| ....' // read the vm stack frame number (optional)
  ... 

[gram, 2013/04/30 01:00:09]

Done.

+
+String _formatStack(stack) {
+  var lines;
+  if (stack is StackTrace) {
+    lines = stack.toString().split('\n');
+  } else if (stack is String) {
+    lines = stack.split('\n');
+  } else {
+    return stack.toString();
+  }
+ 
+  // Calculate the max width of first column so we can 
+  // pad to align the second columns.
+  int padding = lines.fold(0, (n, line) {
+    var match = _frameRegExp.firstMatch(line);
+    if (match == null) return n;
+    return match[1].length + 1;

[Siggi Cherem (dart-lang), 2013/04/30 00:42:33]

missing call to max(n, *) here?

[gram, 2013/04/30 01:00:09]

Done.

+  });
+
+  // We remove all entries that have a location in unittest.
+  // We strip out anything before _nextBatch too.
+  var sb = new StringBuffer();
+  for (var i = 0; i < lines.length; i++) {
+    var line = lines[i];
+    if (line == '') continue;
+    var match = _frameRegExp.firstMatch(line);
+    if (match == null) {
+      sb.write(line);
+      sb.write('\n');
+    } else {
+      var member = match[1];
+      var location = match[2];
+      var position = match[3];
+      if (member.indexOf('TestCase._runTest') >= 0) {
+        // Don't include anything after this.
+        break;
+      } else if (member.indexOf('expect') >= 0) {
+        // It looks like this was an expect() failure;
+        // drop all the frames up to here.
+        sb.clear();
+      } else {
+        sb.write(member);
+        // Pad second column to a fixed position.
+        for (var j = 0; j <= padding - member.length; j++) {
+          sb.write(' ');
+        }
+        sb.write(location);
+        sb.write(' ');
+        sb.write(position);
+        sb.write('\n');
+      }
+    }
+  }
+  return sb.toString();
+}