CLI driver test re-enablement (#25001).

pkg/analyzer_cli/lib/src/options.dart

Index: pkg/analyzer_cli/lib/src/options.dart
diff --git a/pkg/analyzer_cli/lib/src/options.dart b/pkg/analyzer_cli/lib/src/options.dart
index ee683e2d084e7eb1a190f6aa8a6ff833fa297fc3..7da6bb41e0ca0edbded103493cf6016572603cfe 100644
--- a/pkg/analyzer_cli/lib/src/options.dart
+++ b/pkg/analyzer_cli/lib/src/options.dart
@@ -17,7 +17,7 @@ const _binaryName = 'dartanalyzer';
 /// *Visible for testing.*
 ExitHandler exitHandler = exit;
 
-/// Print the given message to stderr and exit with the given [exitCode]
+/// Print the given [message] to stderr and exit with the given [exitCode].
 void printAndFail(String message, {int exitCode: 15}) {
   errorSink.writeln(message);
   exitHandler(exitCode);
@@ -163,8 +163,9 @@ class CommandLineOptions {
 
     // OK.  Report deprecated options.
     if (options.enableNullAwareOperators) {
-      stderr.writeln(
-          "Info: Option '--enable-null-aware-operators' is no longer needed. Null aware operators are supported by default.");
+      errorSink.writeln(
+          "Info: Option '--enable-null-aware-operators' is no longer needed. "
+          "Null aware operators are supported by default.");
     }
 
     return options;
@@ -194,11 +195,13 @@ class CommandLineOptions {
       ..addOption('dart-sdk', help: 'The path to the Dart SDK.')
       ..addOption('packages',
           help:
-              'Path to the package resolution configuration file, which supplies a mapping of package names to paths.  This option cannot be used with --package-root.')
+              'Path to the package resolution configuration file, which supplies '
+              'a mapping of package names to paths.  This option cannot be '
+              'used with --package-root.')
       ..addOption('package-root',
           abbr: 'p',
-          help:
-              'Path to a package root directory (deprecated). This option cannot be used with --packages.')
+          help: 'Path to a package root directory (deprecated). This option '
+              'cannot be used with --packages.')
       ..addOption('options', help: 'Path to an analysis options file.')
       ..addOption('format',
           help: 'Specifies the format in which errors are displayed.')
@@ -308,45 +311,50 @@ class CommandLineOptions {
       // Help requests.
       if (results['help']) {
         _showUsage(parser);
-        exit(0);
+        exitHandler(0);
+        return null; // Only reachable in testing.
       }
       // Batch mode and input files.
       if (results['batch']) {
         if (results.rest.isNotEmpty) {
-          stderr.writeln('No source files expected in the batch mode.');
+          errorSink.writeln('No source files expected in the batch mode.');
           _showUsage(parser);
-          exit(15);
+          exitHandler(15);
+          return null; // Only reachable in testing.
         }
       } else if (results['version']) {
-        print('$_binaryName version ${_getVersion()}');
-        exit(0);
+        outSink.write('$_binaryName version ${_getVersion()}');
+        exitHandler(0);
+        return null; // Only reachable in testing.
       } else {
         if (results.rest.isEmpty) {
           _showUsage(parser);
-          exit(15);
+          exitHandler(15);
+          return null; // Only reachable in testing.
         }
       }
       return new CommandLineOptions._fromArgs(results, definedVariables);
     } on FormatException catch (e) {
-      stderr.writeln(e.message);
+      errorSink.writeln(e.message);
       _showUsage(parser);
-      exit(15);
+      exitHandler(15);
+      return null; // Only reachable in testing.
     }
   }
 
   static _showUsage(parser) {
-    stderr
+    errorSink
         .writeln('Usage: $_binaryName [options...] <libraries to analyze...>');
-    stderr.writeln(parser.getUsage());
-    stderr.writeln('');
-    stderr.writeln(
+    errorSink.writeln(parser.getUsage());
+    errorSink.writeln('');
+    errorSink.writeln(
         'For more information, see http://www.dartlang.org/tools/analyzer.');
   }
 }
 
 /// Commandline argument parser.
 ///
-/// TODO(pquitslund): when the args package supports ignoring unrecognized
+/// TODO(pq): when the args package supports ignoring unrecognized
 /// options/flags, this class can be replaced with a simple [ArgParser]
 /// instance.
 class CommandLineParser {