Update link to JS tests inside of interface-ipfs-core (#860)

Author: victorb

README.md

@@ -465,7 +465,7 @@ The js-ipfs-api is a work in progress. As such, there's a few things you can do
 
 * **[Check out the existing issues](https://github.com/ipfs/js-ipfs-api/issues)**!
 * **Perform code reviews**. More eyes will help a) speed the project along b) ensure quality and c) reduce possible future bugs.
-* **Add tests**. There can never be enough tests. Note that interface tests exist inside [`interface-ipfs-core`](https://github.com/ipfs/interface-ipfs-core/tree/master/src).
+* **Add tests**. There can never be enough tests. Note that interface tests exist inside [`interface-ipfs-core`](https://github.com/ipfs/interface-ipfs-core/tree/master/js/src).
 * **Contribute to the [FAQ repository](https://github.com/ipfs/faq/issues)** with any questions you have about IPFS or any of the relevant technology. A good example would be asking, 'What is a merkledag tree?'. If you don't know a term, odds are, someone else doesn't either. Eventually, we should have a good understanding of where we need to improve communications and teaching together to make IPFS and IPN better.
 
 **Want to hack on IPFS?**