Revert "Use runTests in fuchsia tester. (#19178)" (#19321)

This reverts commit 032f8cdb.

The test runner hangs on exit after all tests pass when trying
to roll this into Fuchsia.

packages/flutter_tools/bin/fuchsia_tester.dart

@@ -11,12 +11,12 @@ import 'package:flutter_tools/src/base/io.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/context_runner.dart';
 import 'package:flutter_tools/src/dart/package_map.dart';
-import 'package:flutter_tools/src/artifacts.dart';
 import 'package:flutter_tools/src/disabled_usage.dart';
 import 'package:flutter_tools/src/globals.dart';
-import 'package:flutter_tools/src/test/coverage_collector.dart';
-import 'package:flutter_tools/src/test/runner.dart';
+import 'package:flutter_tools/src/test/flutter_platform.dart' as loader;
 import 'package:flutter_tools/src/usage.dart';
+import 'package:test/src/executable.dart'
+    as test; // ignore: implementation_imports
 
 // Note: this was largely inspired by lib/src/commands/test.dart.
 
@@ -28,8 +28,6 @@ const List<String> _kRequiredOptions = const <String>[
   _kOptionShell,
   _kOptionTestDirectory,
 ];
-const String _kOptionCoverage = 'coverage';
-const String _kOptionCoveragePath = 'coverage-path';
 
 Future<Null> main(List<String> args) {
   return runInContext<Null>(() => run(args), overrides: <Type, dynamic>{
@@ -49,20 +47,12 @@ Future<Null> run(List<String> args) async {
   final ArgParser parser = new ArgParser()
     ..addOption(_kOptionPackages, help: 'The .packages file')
     ..addOption(_kOptionShell, help: 'The Flutter shell binary')
-    ..addOption(_kOptionTestDirectory, help: 'Directory containing the tests')
-    ..addFlag(_kOptionCoverage,
-      defaultsTo: false,
-      negatable: false,
-      help: 'Whether to collect coverage information.',
-    )
-    ..addOption(_kOptionCoveragePath,
-        defaultsTo: 'coverage/lcov.info',
-        help: 'Where to store coverage information (if coverage is enabled).',
-    );
+    ..addOption(_kOptionTestDirectory, help: 'Directory containing the tests');
   final ArgResults argResults = parser.parse(args);
   if (_kRequiredOptions
       .any((String option) => !argResults.options.contains(option))) {
-    throwToolExit('Missing option! All options must be specified.');
+    printError('Missing option! All options must be specified.');
+    exit(1);
   }
   final Directory tempDirectory =
       fs.systemTempDirectory.createTempSync('fuchsia_tester');
@@ -80,36 +70,16 @@ Future<Null> run(List<String> args) async {
     if (!fs.isFileSync(shellPath)) {
       throwToolExit('Cannot find Flutter shell at $shellPath');
     }
-    // Put the tester shell where runTests expects it.
-    // TODO(tvolkert,garymm): Switch to a Fuchsia-specific Artifacts impl.
-    final Link testerDestLink =
-        fs.link(artifacts.getArtifactPath(Artifact.flutterTester));
-    testerDestLink.parent.createSync(recursive: true);
-    testerDestLink.createSync(shellPath);
+    loader.installHook(
+      shellPath: shellPath,
+    );
 
     PackageMap.globalPackagesPath =
         fs.path.normalize(fs.path.absolute(argResults[_kOptionPackages]));
+    fs.currentDirectory = testDirectory;
 
-    CoverageCollector collector;
-    if (argResults['coverage']) {
-      collector = new CoverageCollector();
-    }
-
-    exitCode = await runTests(
-      tests,
-      workDir: testDirectory,
-      watcher: collector,
-      enableObservatory: collector != null,
-    );
-
-    if (collector != null) {
-      // collector expects currentDirectory to be the root of the dart
-      // package (i.e. contains lib/ and test/ sub-dirs).
-      fs.currentDirectory = testDirectory.parent;
-      if (!await
-          collector.collectCoverageData(argResults[_kOptionCoveragePath]))
-        throwToolExit('Failed to collect coverage data');
-    }
+    await test.main(testArgs);
+    exit(exitCode);
   } finally {
     tempDirectory.deleteSync(recursive: true);
   }