refactor(test): reduce cognitive complexity of the test runners

.gitignore

@@ -15,6 +15,9 @@ doc/api/
 # Files generated during tests
 .test_coverage.dart
 coverage/
+# The coverage library and its tests are sources, not reports.
+!lib/src/coverage/
+!test/src/coverage/
 .test_optimizer.dart
 !bricks/test_optimizer/__brick__/test/.test_optimizer.dart
 *.vm.json

lib/src/cli/cli.dart

@@ -2,23 +2,24 @@ import 'dart:async';
 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:mason/mason.dart';
 import 'package:meta/meta.dart';
 import 'package:path/path.dart' as p;
 import 'package:pubspec_parse/pubspec_parse.dart';
 import 'package:universal_io/io.dart';
+import 'package:very_good_cli/src/coverage/coverage.dart';
 import 'package:very_good_cli/src/test_optimizer/test_optimizer.dart';
 import 'package:very_good_test_runner/very_good_test_runner.dart';
 
+export 'package:very_good_cli/src/coverage/coverage.dart';
 export 'package:very_good_cli/src/test_optimizer/test_optimizer.dart';
 
 part 'dart_cli.dart';
 part 'flutter_cli.dart';
 part 'git_cli.dart';
 part 'test_cli_runner.dart';
+part 'test_event_reporter.dart';
 
 const R Function<R>(
   R Function(), {

lib/src/cli/flutter_cli.dart

@@ -56,84 +56,6 @@ class _ProcessSignalOverridesScope extends ProcessSignalOverrides {
 /// Thrown when `flutter pub get` is executed without a `pubspec.yaml`.
 class PubspecNotFound implements Exception;
 
-/// {@template coverage_metrics}
-/// Aggregated coverage metrics computed from a list of LCOV records.
-/// {@endtemplate}
-class CoverageMetrics {
-  /// {@macro coverage_metrics}
-  @visibleForTesting
-  const new({
-    this.totalHits = 0,
-    this.totalFound = 0,
-    this.uncoveredLines = const {},
-  });
-
-  /// Generate coverage metrics from a list of lcov records.
-  factory fromLcovRecords(List<Record> records, {String? excludeFromCoverage}) {
-    final globs = <Glob>[];
-
-    if (excludeFromCoverage != null && excludeFromCoverage.isNotEmpty) {
-      for (final glob in excludeFromCoverage.trim().split(' ')) {
-        if (glob.isNotEmpty) globs.add(Glob(glob));
-      }
-    }
-
-    return records.fold<CoverageMetrics>(const CoverageMetrics(), (
-      current,
-      record,
-    ) {
-      final found = record.lines?.found ?? 0;
-      final hit = record.lines?.hit ?? 0;
-      if (globs.isNotEmpty && record.file != null) {
-        for (final glob in globs) {
-          if (glob.matches(record.file!)) return current;
-        }
-      }
-
-      final file = record.file;
-      final details = record.lines?.details;
-      final uncoveredLines = Map<String, List<int>>.from(
-        current.uncoveredLines,
-      );
-
-      if (file != null && details != null) {
-        for (final line in details) {
-          if ((line.hit ?? 1) == 0 && line.line != null) {
-            uncoveredLines.update(
-              file,
-              (lines) => [...lines, line.line!],
-              ifAbsent: () => [line.line!],
-            );
-          }
-        }
-      }
-
-      return CoverageMetrics(
-        totalFound: current.totalFound + found,
-        totalHits: current.totalHits + hit,
-        uncoveredLines: uncoveredLines,
-      );
-    });
-  }
-
-  /// Total number of lines hit (covered) across all included files.
-  final int totalHits;
-
-  /// Total number of instrumented lines found across all included files.
-  final int totalFound;
-
-  /// Lines not covered.
-  /// Keyed by file path, values are sorted line numbers.
-  final Map<String, List<int>> uncoveredLines;
-
-  /// Coverage percentage: [totalHits] / [totalFound] * 100.
-  ///
-  /// Returns `0` when [totalFound] is less than 1.
-  double get percentage {
-    return totalFound < 1 ? 0 : (totalHits / totalFound * 100);
-  }
-}
-
 /// Flutter CLI
 class Flutter {
   /// Determine whether flutter is installed.
@@ -307,53 +229,3 @@ Future<List<T>> _runCommand<T>({
   }
   return results;
 }
-
-// The extension is intended to be unnamed, but it's not possible due to
-// an issue with Dart SDK 2.18.0.
-//
-// Once the min Dart SDK is bumped, this extension can be unnamed again.
-extension _TestEvent on TestEvent {
-  bool shouldCancelTimer() {
-    final event = this;
-    if (event is MessageTestEvent) return true;
-    if (event is ErrorTestEvent) return true;
-    if (event is DoneTestEvent) return true;
-    if (event is TestDoneEvent) return !event.hidden;
-    return false;
-  }
-}
-
-extension on Duration {
-  String formatted() {
-    String twoDigits(int n) => n.toString().padLeft(2, '0');
-    final twoDigitMinutes = twoDigits(inMinutes.remainder(60));
-    final twoDigitSeconds = twoDigits(inSeconds.remainder(60));
-    return darkGray.wrap('$twoDigitMinutes:$twoDigitSeconds')!;
-  }
-}
-
-extension on int {
-  String formatSuccess() {
-    return this > 0 ? lightGreen.wrap('+$this')! : '';
-  }
-
-  String formatFailure() {
-    return this > 0 ? lightRed.wrap('-$this')! : '';
-  }
-
-  String formatSkipped() {
-    return this > 0 ? lightYellow.wrap('~$this')! : '';
-  }
-}
-
-extension on String {
-  String truncated(int maxLength) {
-    if (length <= maxLength) return this;
-    final truncated = substring(length - maxLength, length).trim();
-    return '...$truncated';
-  }
-
-  String toSingleLine() {
-    return replaceAll('\n', '').replaceAll(RegExp(r'\s\s+'), ' ');
-  }
-}