made the negative test more specific

Author: gaaclarke

tools/clang_tidy/test/clang_tidy_test.dart

@@ -140,13 +140,19 @@ void _withTempFile(String prefix, void Function(String path) func) {
   });
 
   test('shard-id invalid', () async {
-    final String variant = path.basename(io.File(buildCommands).parent.path);
-    final Options options = Options.fromCommandLine( <String>[
-        '--shard-variants=$variant',
-        '--shard-id=2',
-      ],);
+    final StringBuffer errBuffer = StringBuffer();
+    final Options options = Options.fromCommandLine(<String>[
+      '--shard-variants=variant',
+      '--shard-id=2',
+    ], errSink: errBuffer);
     expect(options.errorMessage, isNotNull);
     expect(options.shardId, isNull);
+    print('foo ${options.errorMessage}');
+    expect(
+        options.errorMessage,
+        contains(
+          'Invalid shard-id value',
+        ));
   });
 
   test('Error when --compile-commands path does not exist', () async {