Add branch coverage to flutter test (#113802)

Author: liamappelbe

packages/flutter_tools/lib/src/commands/test.dart

@@ -121,6 +121,11 @@ class TestCommand extends FlutterCommand with DeviceBasedDevelopmentArtifacts {
         help: 'Whether to merge coverage data with "coverage/lcov.base.info".\n'
               'Implies collecting coverage data. (Requires lcov.)',
       )
+      ..addFlag('branch-coverage',
+        negatable: false,
+        help: 'Whether to collect branch coverage information. '
+              'Implies collecting coverage data.',
+      )
       ..addFlag('ipv6',
         negatable: false,
         hide: !verboseHelp,
@@ -378,14 +383,16 @@ class TestCommand extends FlutterCommand with DeviceBasedDevelopmentArtifacts {
 
     final bool machine = boolArgDeprecated('machine');
     CoverageCollector? collector;
-    if (boolArgDeprecated('coverage') || boolArgDeprecated('merge-coverage')) {
+    if (boolArgDeprecated('coverage') || boolArgDeprecated('merge-coverage') ||
+        boolArgDeprecated('branch-coverage')) {
       final String projectName = flutterProject.manifest.appName;
       collector = CoverageCollector(
         verbose: !machine,
         libraryNames: <String>{projectName},
         packagesPath: buildInfo.packagesPath,
         resolver: await CoverageCollector.getResolver(buildInfo.packagesPath),
         testTimeRecorder: testTimeRecorder,
+        branchCoverage: boolArgDeprecated('branch-coverage'),
       );
     }
 

packages/flutter_tools/lib/src/test/coverage_collector.dart

@@ -17,7 +17,9 @@ import 'watcher.dart';
 
 /// A class that collects code coverage data during test runs.
 class CoverageCollector extends TestWatcher {
-  CoverageCollector({this.libraryNames, this.verbose = true, required this.packagesPath, this.resolver, this.testTimeRecorder});
+  CoverageCollector({
+      this.libraryNames, this.verbose = true, required this.packagesPath,
+      this.resolver, this.testTimeRecorder, this.branchCoverage = false});
 
   /// True when log messages should be emitted.
   final bool verbose;
@@ -38,6 +40,9 @@ class CoverageCollector extends TestWatcher {
 
   final TestTimeRecorder? testTimeRecorder;
 
+  /// Whether to collect branch coverage information.
+  bool branchCoverage;
+
   static Future<coverage.Resolver> getResolver(String? packagesPath) async {
     try {
       return await coverage.Resolver.create(packagesPath: packagesPath);
@@ -97,7 +102,8 @@ class CoverageCollector extends TestWatcher {
   /// The returned [Future] completes when the coverage is collected.
   Future<void> collectCoverageIsolate(Uri observatoryUri) async {
     _logMessage('collecting coverage data from $observatoryUri...');
-    final Map<String, dynamic> data = await collect(observatoryUri, libraryNames);
+    final Map<String, dynamic> data = await collect(
+        observatoryUri, libraryNames, branchCoverage: branchCoverage);
     if (data == null) {
       throw Exception('Failed to collect coverage.');
     }
@@ -136,7 +142,9 @@ class CoverageCollector extends TestWatcher {
     final Future<void> collectionComplete = testDevice.observatoryUri
       .then((Uri? observatoryUri) {
         _logMessage('collecting coverage data from $testDevice at $observatoryUri...');
-        return collect(observatoryUri!, libraryNames, serviceOverride: serviceOverride)
+        return collect(
+            observatoryUri!, libraryNames, serviceOverride: serviceOverride,
+            branchCoverage: branchCoverage)
           .then<void>((Map<String, dynamic> result) {
             if (result == null) {
               throw Exception('Failed to collect coverage.');
@@ -254,6 +262,10 @@ Future<Map<String, dynamic>> collect(Uri serviceUri, Set<String>? libraryNames,
   String? debugName,
   @visibleForTesting bool forceSequential = false,
   @visibleForTesting FlutterVmService? serviceOverride,
+  bool branchCoverage = false,
 }) {
-  return coverage.collect(serviceUri, false, false, false, libraryNames, serviceOverrideForTesting: serviceOverride?.service);
+  return coverage.collect(
+      serviceUri, false, false, false, libraryNames,
+      serviceOverrideForTesting: serviceOverride?.service,
+      branchCoverage: branchCoverage);
 }

packages/flutter_tools/test/general.shard/coverage_collector_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-@Timeout.factor(10)
-
 import 'dart:convert' show jsonEncode;
 import 'dart:io' show Directory, File;
 
@@ -331,6 +329,97 @@ void main() {
     expect(fakeVmServiceHost.hasRemainingExpectations, false);
   });
 
+  testWithoutContext('Coverage collector with branch coverage', () async {
+    final FakeVmServiceHost fakeVmServiceHost = FakeVmServiceHost(
+      requests: <VmServiceExpectation>[
+        FakeVmServiceRequest(
+          method: 'getVM',
+          jsonResponse: (VM.parse(<String, Object>{})!
+            ..isolates = <IsolateRef>[
+              IsolateRef.parse(<String, Object>{
+                'id': '1',
+              })!,
+            ]
+          ).toJson(),
+        ),
+        FakeVmServiceRequest(
+          method: 'getVersion',
+          jsonResponse: Version(major: 3, minor: 56).toJson(),
+        ),
+        FakeVmServiceRequest(
+          method: 'getScripts',
+          args: <String, Object>{
+            'isolateId': '1',
+          },
+          jsonResponse: ScriptList(scripts: <ScriptRef>[
+            ScriptRef(uri: 'package:foo/foo.dart', id: '1'),
+            ScriptRef(uri: 'package:bar/bar.dart', id: '2'),
+          ]).toJson(),
+        ),
+        FakeVmServiceRequest(
+          method: 'getSourceReport',
+          args: <String, Object>{
+            'isolateId': '1',
+            'reports': <Object>['Coverage', 'BranchCoverage'],
+            'scriptId': '1',
+            'forceCompile': true,
+            'reportLines': true,
+          },
+          jsonResponse: SourceReport(
+            ranges: <SourceReportRange>[
+              SourceReportRange(
+                scriptIndex: 0,
+                startPos: 0,
+                endPos: 0,
+                compiled: true,
+                coverage: SourceReportCoverage(
+                  hits: <int>[1, 3],
+                  misses: <int>[2],
+                ),
+                branchCoverage: SourceReportCoverage(
+                  hits: <int>[4, 6],
+                  misses: <int>[5],
+                ),
+              ),
+            ],
+            scripts: <ScriptRef>[
+              ScriptRef(
+                uri: 'package:foo/foo.dart',
+                id: '1',
+              ),
+            ],
+          ).toJson(),
+        ),
+      ],
+    );
+
+    final Map<String, Object?> result = await collect(
+      Uri(),
+      <String>{'foo'},
+      serviceOverride: fakeVmServiceHost.vmService,
+      branchCoverage: true,
+    );
+
+    expect(result, <String, Object>{
+      'type': 'CodeCoverage',
+      'coverage': <Object>[
+        <String, Object>{
+          'source': 'package:foo/foo.dart',
+          'script': <String, Object>{
+            'type': '@Script',
+            'fixedId': true,
+            'id': 'libraries/1/scripts/package%3Afoo%2Ffoo.dart',
+            'uri': 'package:foo/foo.dart',
+            '_kind': 'library',
+          },
+          'hits': <Object>[1, 1, 3, 1, 2, 0],
+          'branchHits': <Object>[4, 1, 6, 1, 5, 0],
+        },
+      ],
+    });
+    expect(fakeVmServiceHost.hasRemainingExpectations, false);
+  });
+
   testWithoutContext('Coverage collector caches read files', () async {
     Directory? tempDir;
     try {