Add a library for manipulating stack traces.

pkg/stack_trace/test/trace_test.dart

Index: pkg/stack_trace/test/trace_test.dart
diff --git a/pkg/stack_trace/test/trace_test.dart b/pkg/stack_trace/test/trace_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..711a412761bdb5318c73a0512226bebaa5b885c8
--- /dev/null
+++ b/pkg/stack_trace/test/trace_test.dart
@@ -0,0 +1,134 @@
+// 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.
+
+library trace_test;
+
+import 'dart:uri';
+
+import 'package:pathos/path.dart' as path;
+import 'package:stack_trace/stack_trace.dart';
+import 'package:unittest/unittest.dart';
+
+String getStackTraceString() {
+  try {
+    throw '';
+  } catch (_, stackTrace) {
+    return stackTrace.toString();
+  }
+}
+
+StackTrace getStackTraceObject() {
+  try {
+    throw '';
+  } catch (_, stackTrace) {
+    return stackTrace;
+  }
+}
+
+Trace getCurrentTrace([int level]) => new Trace.current(level);
+
+Trace nestedGetCurrentTrace(int level) => getCurrentTrace(level);
+
+void main() {
+  test('parses a stack trace correctly', () {
+    var trace = new Trace.parse('''
+#0      Foo._bar (file:///home/nweiz/code/stuff.dart:42:21)
+#1      zip.<anonymous closure>.zap (dart:async:0:2)
+#2      zip.<anonymous closure>.zap (http://pub.dartlang.org/thing.dart:1:100)
+''');
+
+    expect(trace.frames[0].uri,
+        equals(new Uri.fromString("file:///home/nweiz/code/stuff.dart")));
+    expect(trace.frames[1].uri, equals(new Uri.fromString("dart:async")));
+    expect(trace.frames[2].uri,
+        equals(new Uri.fromString("http://pub.dartlang.org/thing.dart")));
+  });
+
+  test('parses a real stack trace correctly', () {
+    var trace = new Trace.parse(getStackTraceString());
+    // TODO(nweiz): use URL-style paths when such a thing exists.
+    var builder = new path.Builder(style: path.Style.posix);
+    expect(builder.basename(trace.frames.first.uri.path),
+        equals('trace_test.dart'));
+    expect(trace.frames.first.member, equals('getStackTraceString'));
+  });
+
+  test('converts from a native stack trace correctly', () {
+    var trace = new Trace.from(getStackTraceObject());
+    // TODO(nweiz): use URL-style paths when such a thing exists.
+    var builder = new path.Builder(style: path.Style.posix);
+    expect(builder.basename(trace.frames.first.uri.path),
+        equals('trace_test.dart'));
+    expect(trace.frames.first.member, equals('getStackTraceObject'));
+  });
+
+  group('.current()', () {
+    test('with no argument returns a trace starting at the current frame', () {
+      var trace = new Trace.current();
+      expect(trace.frames.first.member, equals('main.<fn>.<fn>'));
+    });
+
+    test('at level 0 returns a trace starting at the current frame', () {
+      var trace = new Trace.current(0);
+      expect(trace.frames.first.member, equals('main.<fn>.<fn>'));
+    });
+
+    test('at level 1 returns a trace starting at the parent frame', () {
+      var trace = getCurrentTrace(1);
+      expect(trace.frames.first.member, equals('main.<fn>.<fn>'));
+    });
+
+    test('at level 2 returns a trace starting at the grandparent frame', () {
+      var trace = nestedGetCurrentTrace(2);
+      expect(trace.frames.first.member, equals('main.<fn>.<fn>'));
+    });
+
+    test('throws an ArgumentError for negative levels', () {
+      expect(() => new Trace.current(-1), throwsArgumentError);
+    });
+  });
+
+  test('.toString() nicely formats the stack trace', () {
+    var absolute = path.absolute(path.join('foo', 'bar.dart'));
+    var trace = new Trace.parse('''
+#0      Foo._bar (file://$absolute:42:21)
+#1      zip.<anonymous closure>.zap (dart:async:0:2)
+#2      zip.<anonymous closure>.zap (http://pub.dartlang.org/thing.dart:1:100)
+''');
+
+    expect(trace.toString(), equals('''
+${path.join('foo', 'bar.dart')} 42:21                        Foo._bar
+dart:async                                zip.<fn>.zap
+http://pub.dartlang.org/thing.dart 1:100  zip.<fn>.zap
+'''));
+  });
+
+  test('.stackTrace forwards to .toString()', () {
+    var trace = new Trace.current();
+    expect(trace.stackTrace, equals(trace.toString()));
+  });
+
+  test('.fullStackTrace forwards to .toString()', () {
+    var trace = new Trace.current();
+    expect(trace.fullStackTrace, equals(trace.toString()));
+  });
+
+  test('.terse folds core frames together bottom-up', () {
+    var trace = new Trace.parse('''
+#0 notCore (foo.dart:42:21)
+#1 top (dart:async:0:2)
+#2 bottom (dart:core:1:100)
+#3 alsoNotCore (bar.dart:10:20)
+#4 top (dart:io:5:10)
+#5 bottom (dart:async-patch:9:11)
+''');
+
+    expect(trace.terse.toString(), equals('''
+foo.dart 42:21  notCore
+dart:core       bottom
+bar.dart 10:20  alsoNotCore
+dart:async      bottom
+'''));
+  });
+}