tests-polyfill failing under Node with: Warning: Required config property "clean.w3c-old" missing.

[aral]

Node: v8.11.1 Platform: macOS 10.13.4 (17E202)

Followed instructions at https://github.com/aral/IndexedDBShim/blob/master/docs/TESTING.md - failed at step 3 with the following error:

npm run tests-polyfill

> indexeddbshim@3.6.2 tests-polyfill /Users/aral/sandbox/IndexedDBShim
> grunt clean-polyfill && npm run fake && npm run mock && npm run w3c-old && browserify-test -t [ babelify --presets es2015 ] tests-polyfill/**/*.js

(node:78964) ExperimentalWarning: The http2 module is an experimental API.
Running "clean:fake" (clean) task
>> 0 paths cleaned.

Running "clean:mock" (clean) task
>> 0 paths cleaned.

Running "clean:w3c-old" (clean) task
Verifying property clean.w3c-old exists in config...ERROR
>> Unable to process task.
Warning: Required config property "clean.w3c-old" missing. Use --force to continue.

Aborted due to warnings.
npm ERR! code ELIFECYCLE
npm ERR! errno 3
npm ERR! indexeddbshim@3.6.2 tests-polyfill: `grunt clean-polyfill && npm run fake && npm run mock && npm run w3c-old && browserify-test -t [ babelify --presets es2015 ] tests-polyfill/**/*.js`
npm ERR! Exit status 3
npm ERR!
npm ERR! Failed at the indexeddbshim@3.6.2 tests-polyfill script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/aral/.npm/_logs/2018-05-23T11_42_41_401Z-debug.log

[aral]

This might be because I didn’t do a recursive clone of the repository (as per https://github.com/aral/IndexedDBShim#building). If so, please feel free to close it if it is expected behaviour. (Although perhaps a note in the testing section will help others avoid the confusion.)