[flutter_tools] check in script for generating per library unit coverage (#61996)
Allows generating a per-library coverage summary like https://gist.github.com/jonahwilliams/f298381c3fb9f472b2dfe54b82a20a88
diff --git a/packages/flutter_tools/test/integration.shard/unit_coverage_test.dart b/packages/flutter_tools/test/integration.shard/unit_coverage_test.dart
new file mode 100644
index 0000000..7433d54
--- /dev/null
+++ b/packages/flutter_tools/test/integration.shard/unit_coverage_test.dart
@@ -0,0 +1,68 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/base/io.dart';
+import 'package:flutter_tools/src/globals.dart' as globals;
+import 'package:process/process.dart';
+
+import '../src/common.dart';
+import 'test_utils.dart';
+
+void main() {
+ Directory tempDir;
+
+ setUp(() async {
+ tempDir = createResolvedTempDirectorySync('unit_coverage_test.');
+ });
+
+ tearDown(() async {
+ tryToDelete(tempDir);
+ });
+
+ test('Can parse and output summaries for code coverage', () async {
+ final File coverageFile = tempDir.childFile('info.lcov')
+ ..writeAsStringSync('''
+SF:lib/src/artifacts.dart
+DA:15,10
+DA:17,7
+DA:19,7
+DA:20,7
+DA:22,7
+DA:324,10
+DA:724,0
+DA:727,2
+DA:729,3
+DA:732,0
+DA:737,1
+LF:443
+LH:292
+end_of_record
+SF:lib/src/base/common.dart
+DA:13,7
+DA:14,7
+DA:22,7
+DA:27,3
+DA:28,6
+DA:40,7
+LF:6
+LH:6
+end_of_record
+''');
+
+ final String dartScript = globals.fs.path.join(getFlutterRoot(), 'bin', 'dart');
+ final String coverageScript = globals.fs.path.join(getFlutterRoot(), 'packages', 'flutter_tools', 'tool', 'unit_coverage.dart');
+ final ProcessResult result = await const LocalProcessManager().run(<String>[
+ dartScript,
+ coverageScript,
+ coverageFile.path,
+ ]);
+
+ // May contain other output if building flutter tool.
+ expect(result.stdout.toString().split('\n'), containsAll(<Matcher>[
+ contains('lib/src/artifacts.dart: 81.82%'),
+ contains('lib/src/base/common.dart: 100.00%'),
+ ]));
+ });
+}
diff --git a/packages/flutter_tools/tool/unit_coverage.dart b/packages/flutter_tools/tool/unit_coverage.dart
new file mode 100644
index 0000000..f55b4f4
--- /dev/null
+++ b/packages/flutter_tools/tool/unit_coverage.dart
@@ -0,0 +1,51 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:io';
+
+/// Produces a per-library coverage summary when fed an lcov file, sorted by
+/// increasing code coverage percentage.
+///
+/// Usage: `dart tool/unit_coverage lcov.info`
+void main(List<String> args) {
+ if (args.isEmpty || args.length > 1) {
+ print('Usage: dart tool/unit_coverage lcov.info');
+ return;
+ }
+ final List<String> lines = File(args.single).readAsLinesSync();
+ final List<Coverage> coverages = <Coverage>[];
+ Coverage currentCoverage;
+
+ for (final String line in lines) {
+ if (line.startsWith('SF:')) {
+ final String library = line.split('SF:')[1];
+ currentCoverage = Coverage()..library = library;
+ coverages.add(currentCoverage);
+ }
+ if (line.startsWith('DA')) {
+ currentCoverage.totalLines += 1;
+ if (!line.endsWith(',0')) {
+ currentCoverage.testedLines += 1;
+ }
+ }
+ if (line == 'end_of_record') {
+ currentCoverage = null;
+ }
+ }
+ coverages.sort((Coverage left, Coverage right) {
+ final double leftPercent = left.testedLines / left.totalLines;
+ final double rightPercent = right.testedLines / right.totalLines;
+ return leftPercent.compareTo(rightPercent);
+ });
+ for (final Coverage coverage in coverages) {
+ final String coveragePercent = (coverage.testedLines / coverage.totalLines * 100).toStringAsFixed(2);
+ print('${coverage.library}: $coveragePercent%');
+ }
+}
+
+class Coverage {
+ String library;
+ int totalLines = 0;
+ int testedLines = 0;
+}
