Fix tools/full-coverage.dart script and add standalone test

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';
+import 'package:unittest/unittest.dart';
+
+final String coverageScript = "tools/full-coverage.dart";
+final String packageRoot = Platform.packageRoot;
+final String sdkRoot = join(dirname(Platform.executable), 'dart-sdk');
+final List dartBaseArgs = ['--package-root=${packageRoot}', '--checked',];
+
+// 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': '''
+dummy () {
+  for (int i = 0; i < 100; i++) {
+    print(i);
+  }
+}
+
+int fac(int n) {
+  int f = 1;
+  for (int i = 1; i <= n; i++) {
+    f *= i;
+  }
+  return f;
+}
+
+main() {
+  if (false) {
+    dummy(11);
+  } else {
+    fac(10);
+  }
+}
+''',
+    'expectedHits': [-1, 0, 0, -1, -1, -1, -1, -1, 1, 1, -1, -1, -1, -1, -1, -1,
+                     0, -1, 1, -1, -1]
+  }
+];

[Ivan Posva, 2014/06/20 18:27:16]

Are you planning to add more tests? Such as tests with closures and similar?

[Michael Lippautz (Google), 2014/06/20 19:31:45]

Added a test covering closures.

+
+
+String prepareEnv() {
+  Directory testDir = Directory.systemTemp.createTempSync("coverage-");
+  for (var coverageProg in coverageTests) {
+    var coverageProgDir = new Directory(
+        join(testDir.path, coverageProg["name"]))

[Ivan Posva, 2014/06/20 18:27:16]

It is really confusing to be using these top-level functions from imported
packages without a prefix on the import.

[Michael Lippautz (Google), 2014/06/20 19:31:45]

Done.

+      ..createSync();
+    var f = new File(join(coverageProgDir.path,
+        "${coverageProg['name']}.dart"));
+    f.writeAsStringSync(coverageProg["program"], mode: FileMode.WRITE);
+  }
+  return testDir.path;
+}
+
+
+destroyEnv(base) => new Directory(base).deleteSync(recursive: true);
+
+
+generateCoverage(String workingDirectory) {
+  for (var coverageProg in coverageTests) {
+    var progPath = join(workingDirectory, coverageProg['name']);
+    var script = join(progPath, "${coverageProg['name']}.dart");
+    var dartArgs = new List.from(dartBaseArgs)
+      ..addAll(['--coverage-dir=${progPath}', '${script}']);
+    var result = Process.runSync(Platform.executable, dartArgs);
+    expect(result.exitCode, 0);
+  }
+}
+
+
+Future<Process> convertCoverage(String programDir, String format) {
+  var dartArgs = new List.from(dartBaseArgs)
+      ..addAll([
+        coverageScript,
+        '--package-root=${packageRoot}',
+        '--sdk-root=${sdkRoot}',
+        '--in=${programDir}',
+        format
+      ]);
+  return Process.start(Platform.executable, dartArgs);
+}
+
+
+class PrettyPrintDescriptor {
+  var _programPath;
+  var _validFormat = new RegExp(r"^\s*\d*\|.*$", multiLine: true);
+  var _pattern = new RegExp(r"^\s*(\d+)\|", multiLine: true);
+
+  PrettyPrintDescriptor(this._programPath);
+
+  get sectionStart => _programPath;
+  get sectionEnd => '/';
+  get coverageParameter => '--pretty-print';
+
+  hitData(line) {
+    expect(_validFormat.hasMatch(line), isTrue);
+    var match = _pattern.firstMatch(line);
+    var result = -1;
+    if (match != null) {
+      result = (int.parse(match.group(1)) != 0) ? 1 : 0;
+    }
+    return [result];
+  }
+}
+
+
+class LcovDescriptor {
+  var _pattern = new RegExp(r"^DA:(\d+),(\d+)$", multiLine: true);
+  var _programPath;
+  var _line_nr = 0;
+
+  LcovDescriptor(this._programPath);
+
+  get sectionStart => 'SF:${_programPath}';
+  get sectionEnd => 'end_of_record';
+  get coverageParameter => '--lcov';
+
+  hitData(line) {
+    expect(_pattern.hasMatch(line), isTrue);
+    var match = _pattern.firstMatch(line);
+    // Lcov data starts at line 1, we start at 0.
+    var out_line = int.parse(match[1]) - 1;
+    var hitCount = int.parse(match[2]);
+    var result = [];
+    for ( ; _line_nr < out_line; _line_nr++) {
+      result.add(-1);
+    }
+    result.add((hitCount != 0) ? 1 : 0);
+    _line_nr++;
+    return result;
+  }
+}
+
+
+Stream filterHitData(input, descriptor) {
+  bool in_program_section = false;
+  return input.where((line) {
+    if (in_program_section) {
+      if (line.startsWith(descriptor.sectionEnd)) {
+        in_program_section = false;
+        return false;
+      }
+      return true;
+    }
+    if (line.startsWith(descriptor.sectionStart)) {
+      in_program_section = true;
+    }
+    return false;
+  }).map((line) {
+    return descriptor.hitData(line);
+  });
+}
+
+
+testCoverage(String programDir, String programPath, descriptor,
+             List expectedHitMap) {
+  var p = convertCoverage(programDir, descriptor.coverageParameter);
+  expect(p.then((process) {
+    var hitStream = filterHitData(
+        process.stdout.transform(UTF8.decoder)
+                      .transform(const LineSplitter()),
+        descriptor);
+    var hitMap = [];
+    var subscription = hitStream.listen((data) {
+      // Flatten results.
+      data.forEach((e) => hitMap.add(e));
+    });
+    expect(subscription.asFuture().then((_) {
+      hitMap.forEach((e) {
+        expect(e, expectedHitMap.removeAt(0));
+      });
+      // 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;
+
+  setUp(() {
+    testingDirectory = prepareEnv();
+  });
+
+  tearDown(() => destroyEnv(testingDirectory));
+
+  test('CoverageTests', () {
+    generateCoverage(testingDirectory);
+
+    coverageTests.forEach((cTest) {
+      String programDir = join(testingDirectory, cTest['name']);
+      String programPath = join(programDir, "${cTest['name']}.dart");
+      testCoverage(programDir, programPath,
+                   new LcovDescriptor(programPath),
+                   new List.from(cTest['expectedHits']));
+      testCoverage(programDir, programPath,
+                   new PrettyPrintDescriptor(programPath),
+                   new List.from(cTest['expectedHits']));
+    });
+  });
+}