feat: add coverage merge command

.github/workflows/e2e.yaml

@@ -37,6 +37,9 @@ jobs:
           - test/commands/test/spaced_golden_file_name/spaced_golden_file_name_test.dart
           - test/commands/test/very_good_config/very_good_config_test.dart
 
+          # E2E tests for the coverage command
+          - test/commands/coverage/merge/merge_test.dart
+
           # E2E tests for the create command
           - test/commands/create/flutter_app/core_test.dart
           - test/commands/create/dart_cli/dart_cli_test.dart

.gitignore

@@ -15,6 +15,9 @@ doc/api/
 # Files generated during tests
 .test_coverage.dart
 coverage/
+!lib/src/commands/coverage/
+!test/src/commands/coverage/
+!e2e/test/commands/coverage/
 .test_optimizer.dart
 !bricks/test_optimizer/__brick__/test/.test_optimizer.dart
 *.vm.json

README.md

@@ -142,6 +142,18 @@ very_good test -r
 very_good test --platform chrome
 ```
 
+### [`very_good coverage merge`](https://cli.vgv.dev/docs/commands/coverage)
+
+Merge the lcov reports of sharded or recursive test runs, and enforce a minimum coverage on the result.
+
+```sh
+# Merge the reports of every shard and enforce 100% coverage
+very_good coverage merge 'shards/*/lcov.info' --min-coverage 100
+
+# Merge the reports of every package, after `very_good test -r --coverage`
+very_good coverage merge
+```
+
 ### [`very_good packages get`](https://cli.vgv.dev/docs/commands/get_pkgs)
 
 Get packages in a Dart or Flutter project.

e2e/analysis_options.yaml

@@ -1,6 +1,7 @@
 include: package:very_good_analysis/analysis_options.yaml
 analyzer:
   exclude:
+    - test/commands/coverage/merge/fixture/**
     - test/commands/test/**
     - build/**
     - android/**

e2e/test/commands/coverage/merge/fixture/lib/src/add.dart

@@ -0,0 +1,9 @@
+/// Returns [a] + [b].
+int add(int a, int b) {
+  return a + b;
+}
+
+/// Applies [add] to every value of [values], never called by the tests.
+int addAll(List<int> values) {
+  return values.reduce(add);
+}

e2e/test/commands/coverage/merge/fixture/lib/src/multiply.dart

@@ -0,0 +1,9 @@
+/// Returns [a] * [b].
+int multiply(int a, int b) {
+  return a * b;
+}
+
+/// Applies [multiply] to every value of [values], never called by the tests.
+int multiplyAll(List<int> values) {
+  return values.reduce(multiply);
+}

e2e/test/commands/coverage/merge/fixture/lib/src/subtract.dart

@@ -0,0 +1,9 @@
+/// Returns [a] - [b].
+int subtract(int a, int b) {
+  return a - b;
+}
+
+/// Applies [subtract] to every value of [values], never called by the tests.
+int subtractAll(List<int> values) {
+  return values.reduce(subtract);
+}

e2e/test/commands/coverage/merge/fixture/pubspec.yaml

@@ -0,0 +1,15 @@
+name: coverage_merge_fixture
+description: Fixture for testing the merge of sharded coverage reports.
+version: 0.1.0+1
+publish_to: none
+
+environment:
+  sdk: ^3.13.0
+
+dependencies:
+  flutter:
+    sdk: flutter
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter

e2e/test/commands/coverage/merge/fixture/test/add_test.dart

@@ -0,0 +1,8 @@
+import 'package:coverage_merge_fixture/src/add.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test('add', () {
+    expect(add(4, 2), equals(4 + 2));
+  });
+}

e2e/test/commands/coverage/merge/fixture/test/multiply_test.dart

@@ -0,0 +1,8 @@
+import 'package:coverage_merge_fixture/src/multiply.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test('multiply', () {
+    expect(multiply(4, 2), equals(4 * 2));
+  });
+}

e2e/test/commands/coverage/merge/fixture/test/subtract_test.dart

@@ -0,0 +1,8 @@
+import 'package:coverage_merge_fixture/src/subtract.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test('subtract', () {
+    expect(subtract(4, 2), equals(4 - 2));
+  });
+}

e2e/test/commands/coverage/merge/merge_test.dart

@@ -0,0 +1,105 @@
+import 'package:mason/mason.dart';
+import 'package:mocktail/mocktail.dart';
+import 'package:path/path.dart' as path;
+import 'package:test/test.dart';
+import 'package:universal_io/io.dart';
+import 'package:very_good_cli/src/cli/cli.dart';
+
+import '../../../../helpers/helpers.dart';
+
+/// The records of the lcov report at [filePath], merged and serialized per
+/// source file, so reports listing the same files in a different order compare
+/// equal while lines moved between files do not.
+Map<String, String> _recordsByFile(String filePath) => {
+  for (final record in mergeLcovRecords(
+    parseLcov(File(filePath).readAsStringSync()),
+  ))
+    record.file: record.toLcov(),
+};
+
+void main() {
+  test(
+    'merges sharded coverage into the coverage of an unsharded run',
+    timeout: const Timeout(Duration(minutes: 5)),
+    withRunner((commandRunner, logger, updater, logs, progressLogs) async {
+      final tempDirectory = Directory.systemTemp.createTempSync('merge');
+      addTearDown(() => tempDirectory.deleteSync(recursive: true));
+
+      await copyDirectory(
+        Directory(
+          path.join(
+            Directory.current.path,
+            'test/commands/coverage/merge/fixture',
+          ),
+        ),
+        tempDirectory,
+      );
+      await expectSuccessfulProcessResult('flutter', [
+        'pub',
+        'get',
+      ], workingDirectory: tempDirectory.path);
+
+      final cwd = Directory.current;
+      Directory.current = tempDirectory;
+      addTearDown(() => Directory.current = cwd);
+
+      final lcovPath = path.join('coverage', 'lcov.info');
+
+      await expectLater(
+        commandRunner.run(['test', '--coverage']),
+        completion(equals(ExitCode.success.code)),
+      );
+      final unshardedPath = File(lcovPath).copySync('unsharded.info').path;
+
+      for (final shard in ['1', '2']) {
+        await expectLater(
+          commandRunner.run([
+            'test',
+            '--coverage',
+            '--shard-index',
+            shard,
+            '--total-shards',
+            '2',
+          ]),
+          completion(equals(ExitCode.success.code)),
+        );
+        final shardPath = path.join('shards', shard, 'lcov.info');
+        Directory(path.dirname(shardPath)).createSync(recursive: true);
+        File(lcovPath).copySync(shardPath);
+      }
+
+      await expectLater(
+        commandRunner.run([
+          'coverage',
+          'merge',
+          'shards/*/lcov.info',
+          '--output',
+          'merged.info',
+        ]),
+        completion(equals(ExitCode.success.code)),
+      );
+      expect(
+        _recordsByFile('merged.info'),
+        equals(_recordsByFile(unshardedPath)),
+      );
+
+      await expectLater(
+        commandRunner.run([
+          'coverage',
+          'merge',
+          'shards/*/lcov.info',
+          '--output',
+          'merged.info',
+          '--min-coverage',
+          '100',
+        ]),
+        completion(equals(ExitCode.software.code)),
+      );
+      verify(
+        () => logger.err(
+          any(that: startsWith('Expected coverage >= 100.00% but actual is ')),
+        ),
+      ).called(1);
+    }),
+  );
+}

lib/src/cli/cli.dart

@@ -1,10 +1,11 @@
 import 'dart:async';
+import 'dart:convert';
 import 'dart:math';
 
 import 'package:collection/collection.dart';
 import 'package:coverage/coverage.dart' as coverage;
 import 'package:glob/glob.dart';
-import 'package:lcov_parser/lcov_parser.dart';
+import 'package:glob/list_local_fs.dart';
 import 'package:mason/mason.dart';
 import 'package:meta/meta.dart';
 import 'package:path/path.dart' as p;
@@ -15,9 +16,11 @@ import 'package:very_good_test_runner/very_good_test_runner.dart';
 
 export 'package:very_good_cli/src/test_optimizer/test_optimizer.dart';
 
+part 'coverage_check.dart';
 part 'dart_cli.dart';
 part 'flutter_cli.dart';
 part 'git_cli.dart';
+part 'lcov.dart';
 part 'test_cli_runner.dart';
 
 const R Function<R>(
@@ -187,11 +190,24 @@ const _ignoredDirectories = {
   '.fvm',
 };
 
+/// Whether the relative [path] goes through a platform, build or tool
+/// directory, which recursive commands skip.
+bool isInIgnoredDirectory(String path) =>
+    p.split(path).any(_ignoredDirectories.contains);
+
 bool _isPubspec(FileSystemEntity entity) {
   if (entity is! File) return false;
   return p.basename(entity.path) == 'pubspec.yaml';
 }
 
+/// Whether [entity] is the `pubspec.yaml` of a package that recursive commands
+/// run on, skipping platform, build and tool directories and the [ignore]d
+/// ones.
+bool _isPackagePubspec(
+  FileSystemEntity entity, {
+  Set<String> ignore = const {},
+}) => _isPubspec(entity) && !ignore.excludes(entity);
+
 extension on Set<String> {
   bool excludes(FileSystemEntity entity) {
     final segments = p.split(entity.path).toSet();