Add --fail-under flag for minimum coverage threshold

pkgs/coverage/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 1.13.0
+
+- Introduced support for minimum coverage thresholds using --fail-under flag in
+  format_coverage..
+
 ## 1.12.0
 
 - Introduced support for specifying coverage flags through a YAML file.

pkgs/coverage/bin/format_coverage.dart

@@ -7,6 +7,7 @@ import 'dart:io';
 import 'package:args/args.dart';
 import 'package:coverage/coverage.dart';
 import 'package:coverage/src/coverage_options.dart';
+import 'package:coverage/src/coverage_percentage.dart';
 import 'package:glob/glob.dart';
 import 'package:path/path.dart' as p;
 
@@ -30,6 +31,7 @@ class Environment {
     required this.sdkRoot,
     required this.verbose,
     required this.workers,
+    required this.failUnder,
   });
 
   String? baseDirectory;
@@ -49,6 +51,7 @@ class Environment {
   String? sdkRoot;
   bool verbose;
   int workers;
+  double? failUnder;
 }
 
 Future<void> main(List<String> arguments) async {
@@ -130,6 +133,28 @@ Future<void> main(List<String> arguments) async {
     }
   }
   await outputSink.close();
+
+  // Check coverage against the fail-under threshold if specified
+  if (env.failUnder != null) {
+    // Calculate the overall coverage percentage using the utility function
+    final result = calculateCoveragePercentage(
+      hitmap,
+    );
+
+    if (env.verbose) {
+      print('Coverage: ${result.percentage.toStringAsFixed(2)}% '
+          '(${result.coveredLines} of ${result.totalLines} lines)');
+    }
+
+    if (result.percentage < env.failUnder!) {
+      print('Error: Coverage ${result.percentage.toStringAsFixed(2)}% '
+          'is less than required ${env.failUnder}%');
+      exit(1);
+    } else if (env.verbose) {
+      print('Coverage ${result.percentage.toStringAsFixed(2)}% '
+          'meets or exceeds the required ${env.failUnder}%');
+    }
+  }
 }
 
 /// Checks the validity of the provided arguments. Does not initialize actual
@@ -143,6 +168,10 @@ Environment parseArgs(List<String> arguments, CoverageOptions defaultOptions) {
       abbr: 's',
       help: 'path to the SDK root',
     )
+    ..addOption(
+      'fail-under',
+      help: 'Fail if coverage is less than the given percentage (0-100)',
+    )
     ..addOption(
       'packages',
       help: '[DEPRECATED] path to the package spec file',
@@ -308,24 +337,40 @@ Environment parseArgs(List<String> arguments, CoverageOptions defaultOptions) {
   final checkIgnore = args['check-ignore'] as bool;
   final ignoredGlobs = args['ignore-files'] as List<String>;
   final verbose = args['verbose'] as bool;
+
+  double? failUnder;
+  final failUnderStr = args['fail-under'] as String?;
+  if (failUnderStr != null) {
+    try {
+      failUnder = double.parse(failUnderStr);
+      if (failUnder < 0 || failUnder > 100) {
+        fail('--fail-under must be a percentage between 0 and 100');
+      }
+    } catch (e) {
+      fail('Invalid --fail-under value: $e');
+    }
+  }
+
   return Environment(
-      baseDirectory: baseDirectory,
-      bazel: bazel,
-      bazelWorkspace: bazelWorkspace,
-      checkIgnore: checkIgnore,
-      input: input,
-      lcov: lcov,
-      output: output,
-      packagesPath: packagesPath,
-      packagePath: packagePath,
-      prettyPrint: prettyPrint,
-      prettyPrintFunc: prettyPrintFunc,
-      prettyPrintBranch: prettyPrintBranch,
-      reportOn: reportOn,
-      ignoreFiles: ignoredGlobs,
-      sdkRoot: sdkRoot,
-      verbose: verbose,
-      workers: workers);
+    baseDirectory: baseDirectory,
+    bazel: bazel,
+    bazelWorkspace: bazelWorkspace,
+    checkIgnore: checkIgnore,
+    input: input,
+    lcov: lcov,
+    output: output,
+    packagesPath: packagesPath,
+    packagePath: packagePath,
+    prettyPrint: prettyPrint,
+    prettyPrintFunc: prettyPrintFunc,
+    prettyPrintBranch: prettyPrintBranch,
+    reportOn: reportOn,
+    ignoreFiles: ignoredGlobs,
+    sdkRoot: sdkRoot,
+    verbose: verbose,
+    workers: workers,
+    failUnder: failUnder,
+  );
 }
 
 /// Given an absolute path absPath, this function returns a [List] of files

pkgs/coverage/bin/test_with_coverage.dart

@@ -85,6 +85,10 @@ ArgParser _createArgParser(CoverageOptions defaultOptions) => ArgParser()
     defaultsTo: defaultOptions.branchCoverage,
     help: 'Collect branch coverage info.',
   )
+  ..addOption(
+    'fail-under',
+    help: 'Fail if coverage is less than the given percentage (0-100)',
+  )
   ..addMultiOption('scope-output',
       defaultsTo: defaultOptions.scopeOutput,
       help: 'restrict coverage results so that only scripts that start with '
@@ -101,7 +105,8 @@ class Flags {
     this.testScript,
     this.functionCoverage,
     this.branchCoverage,
-    this.scopeOutput, {
+    this.scopeOutput,
+    this.failUnder, {
     required this.rest,
   });
 
@@ -113,6 +118,7 @@ class Flags {
   final bool functionCoverage;
   final bool branchCoverage;
   final List<String> scopeOutput;
+  final String? failUnder;
   final List<String> rest;
 }
 
@@ -169,6 +175,7 @@ ${parser.usage}
     args['function-coverage'] as bool,
     args['branch-coverage'] as bool,
     args['scope-output'] as List<String>,
+    args['fail-under'] as String?,
     rest: args.rest,
   );
 }
@@ -233,6 +240,7 @@ Future<void> main(List<String> arguments) async {
     outJson,
     '-o',
     outLcov,
+    if (flags.failUnder != null) '--fail-under=${flags.failUnder}',
   ]);
   exit(0);
 }

pkgs/coverage/lib/src/coverage_percentage.dart

@@ -0,0 +1,55 @@
+// Copyright (c) 2024, 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.
+
+import 'hitmap.dart';
+
+/// Calculates the coverage percentage from a hitmap.
+///
+/// [hitmap] is the map of file paths to hit maps.
+///
+/// Returns a [CoverageResult] containing the coverage percentage and line
+/// counts.
+CoverageResult calculateCoveragePercentage(Map<String, HitMap> hitmap) {
+  var totalLines = 0;
+  var coveredLines = 0;
+  for (final entry in hitmap.entries) {
+    var coveredBranches = 0;
+    final lineHits = entry.value.lineHits;
+    final branchHits = entry.value.branchHits;
+    totalLines += lineHits.length;
+    if (branchHits != null) {
+      coveredBranches += branchHits.values.where((v) => v > 0).length;
+      totalLines += branchHits.length;
+    }
+    coveredLines +=
+        lineHits.values.where((v) => v > 0).length + coveredBranches;
+  }
+  final coveragePercentage =
+      totalLines > 0 ? coveredLines * 100 / totalLines : 0.0;
+
+  return CoverageResult(
+    percentage: coveragePercentage,
+    coveredLines: coveredLines,
+    totalLines: totalLines,
+  );
+}
+
+/// The result of a coverage calculation.
+class CoverageResult {
+  /// Creates a new [CoverageResult].
+  const CoverageResult({
+    required this.percentage,
+    required this.coveredLines,
+    required this.totalLines,
+  });
+
+  /// The coverage percentage.
+  final double percentage;
+
+  /// The number of covered lines.
+  final int coveredLines;
+
+  /// The total number of lines.
+  final int totalLines;
+}

pkgs/coverage/pubspec.yaml

@@ -1,5 +1,5 @@
 name: coverage
-version: 1.12.0
+version: 1.13.0-wip
 description: Coverage data manipulation and formatting
 repository: https://github.com/dart-lang/tools/tree/main/pkgs/coverage
 issue_tracker: https://github.com/dart-lang/tools/issues?q=is%3Aissue+is%3Aopen+label%3Apackage%3Acoverage

pkgs/coverage/test/coverage_percentage_test.dart

@@ -0,0 +1,75 @@
+// Copyright (c) 2024, 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.
+
+import 'package:coverage/src/coverage_percentage.dart';
+import 'package:coverage/src/hitmap.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('calculateCoveragePercentage', () {
+    test('calculates correct percentage', () {
+      final hitmap = {
+        'file1.dart': HitMap({
+          1: 1, // covered
+          2: 1, // covered
+          3: 0, // not covered
+          4: 1, // covered
+        }),
+        'file2.dart': HitMap({
+          1: 1, // covered
+          2: 0, // not covered
+          3: 0, // not covered
+        }),
+      };
+
+      final result = calculateCoveragePercentage(hitmap);
+
+      // 4 covered lines out of 7 total lines = 57.14%
+      expect(result.percentage.toStringAsFixed(2), equals('57.14'));
+      expect(result.coveredLines, equals(4));
+      expect(result.totalLines, equals(7));
+    });
+    test('handles empty hitmap', () {
+      final hitmap = <String, HitMap>{};
+
+      final result = calculateCoveragePercentage(hitmap);
+
+      expect(result.percentage, equals(0));
+      expect(result.coveredLines, equals(0));
+      expect(result.totalLines, equals(0));
+    });
+
+    test('handles hitmap with no covered lines', () {
+      final hitmap = {
+        'file1.dart': HitMap({
+          1: 0, // not covered
+          2: 0, // not covered
+          3: 0, // not covered
+        }),
+      };
+
+      final result = calculateCoveragePercentage(hitmap);
+
+      expect(result.percentage, equals(0));
+      expect(result.coveredLines, equals(0));
+      expect(result.totalLines, equals(3));
+    });
+
+    test('handles hitmap with all lines covered', () {
+      final hitmap = {
+        'file1.dart': HitMap({
+          1: 1, // covered
+          2: 1, // covered
+          3: 1, // covered
+        }),
+      };
+
+      final result = calculateCoveragePercentage(hitmap);
+
+      expect(result.percentage, equals(100));
+      expect(result.coveredLines, equals(3));
+      expect(result.totalLines, equals(3));
+    });
+  });
+}

pkgs/coverage/test/test_with_coverage_package/lib/validate_lib.dart

@@ -17,3 +17,17 @@ int product(Iterable<int> values) {
   }
   return val;
 }
+
+String evaluateScore(int score) {
+  if (score < 0) {
+    return 'Invalid';
+  } else if (score < 50) {
+    return 'Fail';
+  } else if (score < 70) {
+    return 'Pass';
+  } else if (score <= 100) {
+    return 'Excellent';
+  } else {
+    return 'Overflow';
+  }
+}

pkgs/coverage/test/test_with_coverage_package/test/evaluate_test.dart

@@ -0,0 +1,22 @@
+// Copyright (c) 2022, 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.
+
+import '../lib/validate_lib.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('evaluateScore', () {
+    test('returns Invalid for negative score', () {
+      expect(evaluateScore(-10), equals('Invalid'));
+    });
+
+    test('returns Fail for score < 50', () {
+      expect(evaluateScore(30), equals('Fail'));
+    });
+
+    test('returns Excellent for score 85', () {
+      expect(evaluateScore(85), equals('Excellent'));
+    });
+  });
+}