feat: add --collect-coverage-from option to include untested files in coverage

lib/src/cli/dart_cli.dart

@@ -104,6 +104,7 @@ class Dart {
     Set<String> ignore = const {},
     double? minCoverage,
     String? excludeFromCoverage,
+    CoverageCollectionMode collectCoverageFrom = CoverageCollectionMode.imports,
     String? randomSeed,
     bool? forceAnsi,
     List<String>? arguments,
@@ -122,6 +123,7 @@ class Dart {
       ignore: ignore,
       minCoverage: minCoverage,
       excludeFromCoverage: excludeFromCoverage,
+      collectCoverageFrom: collectCoverageFrom,
       randomSeed: randomSeed,
       forceAnsi: forceAnsi,
       arguments: arguments,

lib/src/cli/flutter_cli.dart

@@ -159,6 +159,7 @@ class Flutter {
     Set<String> ignore = const {},
     double? minCoverage,
     String? excludeFromCoverage,
+    CoverageCollectionMode collectCoverageFrom = CoverageCollectionMode.imports,
     String? randomSeed,
     bool? forceAnsi,
     List<String>? arguments,
@@ -176,6 +177,7 @@ class Flutter {
       ignore: ignore,
       minCoverage: minCoverage,
       excludeFromCoverage: excludeFromCoverage,
+      collectCoverageFrom: collectCoverageFrom,
       randomSeed: randomSeed,
       forceAnsi: forceAnsi,
       arguments: arguments,

lib/src/cli/test_cli_runner.dart

@@ -19,6 +19,24 @@ enum TestRunType {
   dart,
 }
 
+/// How to collect coverage.
+enum CoverageCollectionMode {
+  /// Collect coverage from imported files only (default behavior).
+  imports,
+
+  /// Collect coverage from all files in the project.
+  all
+  ;
+
+  /// Parses a string value into a [CoverageCollectionMode].
+  static CoverageCollectionMode fromString(String value) {
+    return CoverageCollectionMode.values.firstWhere(
+      (mode) => mode.name == value,
+      orElse: () => CoverageCollectionMode.imports,
+    );
+  }
+}
+
 /// A method which returns a [Future<MasonGenerator>] given a [MasonBundle].
 typedef GeneratorBuilder = Future<MasonGenerator> Function(MasonBundle);
 
@@ -72,6 +90,7 @@ class TestCLIRunner {
     Set<String> ignore = const {},
     double? minCoverage,
     String? excludeFromCoverage,
+    CoverageCollectionMode collectCoverageFrom = CoverageCollectionMode.imports,
     String? randomSeed,
     bool? forceAnsi,
     List<String>? arguments,
@@ -197,13 +216,36 @@ class TestCLIRunner {
                   // Write the lcov output to the file.
                   await lcovFile.create(recursive: true);
                   await lcovFile.writeAsString(output);
+
+                  // If collectCoverageFrom is 'all', enhance with untested
+                  // files
+                  if (collectCoverageFrom == CoverageCollectionMode.all) {
+                    await _enhanceLcovWithUntestedFiles(
+                      lcovPath: lcovPath,
+                      cwd: cwd,
+                      reportOn: reportOn ?? 'lib',
+                      excludeFromCoverage: excludeFromCoverage,
+                    );
+                  }
                 }
 
                 if (collectCoverage) {
                   assert(
                     lcovFile.existsSync(),
                     'coverage/lcov.info must exist',
                   );
+
+                  // For Flutter tests with collectCoverageFrom = all, enhance
+                  // lcov
+                  if (testType == TestRunType.flutter &&
+                      collectCoverageFrom == CoverageCollectionMode.all) {
+                    await _enhanceLcovWithUntestedFiles(
+                      lcovPath: lcovPath,
+                      cwd: cwd,
+                      reportOn: 'lib',
+                      excludeFromCoverage: excludeFromCoverage,
+                    );
+                  }
                 }
 
                 if (minCoverage != null) {
@@ -256,6 +298,91 @@ class TestCLIRunner {
     );
   }
 
+  /// Discovers all Dart files in the specified directory for coverage.
+  static List<String> _discoverDartFilesForCoverage({
+    required String cwd,
+    required String reportOn,
+    String? excludeFromCoverage,
+  }) {
+    final reportOnPath = p.join(cwd, reportOn);
+    final directory = Directory(reportOnPath);
+
+    if (!directory.existsSync()) return [];
+
+    final glob = excludeFromCoverage != null ? Glob(excludeFromCoverage) : null;
+
+    return directory
+        .listSync(recursive: true)
+        .whereType<File>()
+        .where((file) => file.path.endsWith('.dart'))
+        .where((file) => glob == null || !glob.matches(file.path))
+        .map((file) => p.relative(file.path, from: cwd))
+        .toList();
+  }
+
+  /// Enhances an existing lcov file by adding uncovered files with 0% coverage.
+  static Future<void> _enhanceLcovWithUntestedFiles({
+    required String lcovPath,
+    required String cwd,
+    required String reportOn,
+    String? excludeFromCoverage,
+  }) async {
+    final lcovFile = File(lcovPath);
+
+    final allDartFiles = _discoverDartFilesForCoverage(
+      cwd: cwd,
+      reportOn: reportOn,
+      excludeFromCoverage: excludeFromCoverage,
+    );
+
+    // Parse existing lcov to find covered files
+    final existingRecords = await Parser.parse(lcovPath);
+    final coveredFiles = existingRecords
+        .where((r) => r.file != null)
+        .map((r) => r.file!)
+        .toSet();
+
+    // Find uncovered files
+    final uncoveredFiles = allDartFiles.where((file) {
+      final normalizedFile = p.normalize(file);
+      for (final covered in coveredFiles) {
+        if (p.normalize(covered).endsWith(normalizedFile)) {
+          return false; // File is covered
+        }
+      }
+      return true; // File is uncovered
+    }).toList();
+
+    if (uncoveredFiles.isEmpty) return;
+
+    // Append uncovered files to lcov
+    final lcovContent = await lcovFile.readAsString();
+    final buffer = StringBuffer(lcovContent);
+
+    for (final file in uncoveredFiles) {
+      final absolutePath = p.join(cwd, file);
+      final dartFile = File(absolutePath);
+      if (dartFile.existsSync()) {
+        final lines = await dartFile.readAsLines();
+        buffer.writeln('SF:${file.replaceAll(r'\', '/')}');
+        // Mark non-trivial lines as uncovered
+        for (var i = 1; i <= lines.length; i++) {
+          final line = lines[i - 1].trim();
+          if (line.isNotEmpty &&
+              !line.startsWith('//') &&
+              !line.startsWith('import') &&
+              !line.startsWith('export') &&
+              !line.startsWith('part')) {
+            buffer.writeln('DA:$i,0');
+          }
+        }
+        buffer.writeln('end_of_record');
+      }
+    }
+
+    await lcovFile.writeAsString(buffer.toString());
+  }
+
   static List<File> _dartCoverageFilesToProcess(String absPath) {
     return Directory(absPath)
         .listSync(recursive: true)

lib/src/commands/dart/commands/dart_test_command.dart

@@ -17,6 +17,7 @@ class DartTestOptions {
     required this.excludeTags,
     required this.tags,
     required this.excludeFromCoverage,
+    required this.collectCoverageFrom,
     required this.randomSeed,
     required this.optimizePerformance,
     required this.failFast,
@@ -36,6 +37,11 @@ class DartTestOptions {
     final excludeTags = argResults['exclude-tags'] as String?;
     final tags = argResults['tags'] as String?;
     final excludeFromCoverage = argResults['exclude-coverage'] as String?;
+    final collectCoverageFromString =
+        argResults['collect-coverage-from'] as String? ?? 'imports';
+    final collectCoverageFrom = CoverageCollectionMode.fromString(
+      collectCoverageFromString,
+    );
     final randomOrderingSeed =
         argResults['test-randomize-ordering-seed'] as String?;
     final randomSeed = randomOrderingSeed == 'random'
@@ -55,6 +61,7 @@ class DartTestOptions {
       excludeTags: excludeTags,
       tags: tags,
       excludeFromCoverage: excludeFromCoverage,
+      collectCoverageFrom: collectCoverageFrom,
       randomSeed: randomSeed,
       optimizePerformance: optimizePerformance,
       failFast: failFast,
@@ -83,6 +90,9 @@ class DartTestOptions {
   /// A glob which will be used to exclude files that match from the coverage.
   final String? excludeFromCoverage;
 
+  /// How to collect coverage.
+  final CoverageCollectionMode collectCoverageFrom;
+
   /// The seed to randomize the execution order of test cases within test files.
   final String? randomSeed;
 
@@ -119,6 +129,7 @@ typedef DartTestCommandCall =
       bool optimizePerformance,
       double? minCoverage,
       String? excludeFromCoverage,
+      CoverageCollectionMode collectCoverageFrom,
       String? randomSeed,
       bool? forceAnsi,
       List<String>? arguments,
@@ -188,6 +199,15 @@ class DartTestCommand extends Command<int> {
         'min-coverage',
         help: 'Whether to enforce a minimum coverage percentage.',
       )
+      ..addOption(
+        'collect-coverage-from',
+        help:
+            'Whether to collect coverage from imported files only or all '
+            'files.',
+        allowed: ['imports', 'all'],
+        defaultsTo: 'imports',
+        valueHelp: 'imports|all',
+      )
       ..addOption(
         'test-randomize-ordering-seed',
         help:
@@ -271,6 +291,7 @@ This command should be run from the root of your Dart project.''');
               options.collectCoverage || options.minCoverage != null,
           minCoverage: options.minCoverage,
           excludeFromCoverage: options.excludeFromCoverage,
+          collectCoverageFrom: options.collectCoverageFrom,
           randomSeed: options.randomSeed,
           forceAnsi: options.forceAnsi,
           arguments: [

lib/src/commands/test/test.dart

@@ -17,6 +17,7 @@ class FlutterTestOptions {
     required this.excludeTags,
     required this.tags,
     required this.excludeFromCoverage,
+    required this.collectCoverageFrom,
     required this.randomSeed,
     required this.optimizePerformance,
     required this.updateGoldens,
@@ -38,6 +39,11 @@ class FlutterTestOptions {
     final excludeTags = argResults['exclude-tags'] as String?;
     final tags = argResults['tags'] as String?;
     final excludeFromCoverage = argResults['exclude-coverage'] as String?;
+    final collectCoverageFromString =
+        argResults['collect-coverage-from'] as String? ?? 'imports';
+    final collectCoverageFrom = CoverageCollectionMode.fromString(
+      collectCoverageFromString,
+    );
     final randomOrderingSeed =
         argResults['test-randomize-ordering-seed'] as String?;
     final randomSeed = randomOrderingSeed == 'random'
@@ -60,6 +66,7 @@ class FlutterTestOptions {
       excludeTags: excludeTags,
       tags: tags,
       excludeFromCoverage: excludeFromCoverage,
+      collectCoverageFrom: collectCoverageFrom,
       randomSeed: randomSeed,
       optimizePerformance: optimizePerformance,
       updateGoldens: updateGoldens,
@@ -90,6 +97,9 @@ class FlutterTestOptions {
   /// A glob which will be used to exclude files that match from the coverage.
   final String? excludeFromCoverage;
 
+  /// How to collect coverage.
+  final CoverageCollectionMode collectCoverageFrom;
+
   /// The seed to randomize the execution order of test cases within test files.
   final String? randomSeed;
 
@@ -134,6 +144,7 @@ typedef FlutterTestCommand =
       bool optimizePerformance,
       double? minCoverage,
       String? excludeFromCoverage,
+      CoverageCollectionMode collectCoverageFrom,
       String? randomSeed,
       bool? forceAnsi,
       List<String>? arguments,
@@ -202,6 +213,15 @@ class TestCommand extends Command<int> {
         'min-coverage',
         help: 'Whether to enforce a minimum coverage percentage.',
       )
+      ..addOption(
+        'collect-coverage-from',
+        help:
+            'Whether to collect coverage from imported files only or all '
+            'files.',
+        allowed: ['imports', 'all'],
+        defaultsTo: 'imports',
+        valueHelp: 'imports|all',
+      )
       ..addOption(
         'test-randomize-ordering-seed',
         help:
@@ -311,6 +331,7 @@ This command should be run from the root of your Flutter project.''');
               options.collectCoverage || options.minCoverage != null,
           minCoverage: options.minCoverage,
           excludeFromCoverage: options.excludeFromCoverage,
+          collectCoverageFrom: options.collectCoverageFrom,
           randomSeed: options.randomSeed,
           forceAnsi: options.forceAnsi,
           arguments: [