Dartdoc_test reports no tests run when everything works

Given this lib/abd.dart

/// This class is excellent
/// ```dart
/// void main() {
///   print('hi');
///   main();
/// }
/// ```
class Foo {}

> dart test
00:01 +0: loading test/dartdoc_test.dart                                                                                       Extracting code samples ...
Analyzing code samples ...
No tests ran.                                                                                                                   
No tests were found.

I would have expected at least a single test to have run. If I make a syntax error it does indeed report a failed test.