Another attempt

test/src/index.ts

@@ -21,6 +21,7 @@ import './common/observablejson.spec';
 import './common/observablestring.spec';
 import './common/observablevector.spec';
 import './common/observablemap.spec';
+import './common/metadata.spec';
 import './common/undoablevector.spec';
 import './common/sanitizer.spec';
 import './common/vdom.spec';