Support for ERC1820 interface ids (#21)

* Add makeInterfaceId.ERC165.

* Add makeInterfaceId.ERC1820.

* Update description.

* Add changelog entry.

* Update CHANGELOG.md

Co-Authored-By: nventuro <nicolas.venturo@gmail.com>

CHANGELOG.md

@@ -3,6 +3,11 @@
 ## 0.4.0 (unreleased)
  * Fix `shouldFail.reverting.withMessage` on non-Ganache chains. ([#25](https://github.com/OpenZeppelin/openzeppelin-test-helpers/pull/25)
  * `shouldFail.reverting.withMessage` fails if no error string is provided. ([#28](https://github.com/OpenZeppelin/openzeppelin-test-helpers/pull/28)
+ * Rename `makeInterfaceId` to `makeInterfaceId.ERC165`, and add `makeInterfaceId.ERC1820`. ([#21](https://github.com/OpenZeppelin/openzeppelin-test-helpers/pull/21)
+
+#### How to upgrade from 0.3
+- Change all occurences of `makeInterfaceId` to `makeInterfaceId.ERC165`.
+- Some uses of `shouldFail.reverting.withMessage` may fail now. This means it was being used incorrectly and an error string to match against should be added. Alternatively, if the error message is unknown, use `shouldFail.reverting` instead.
 
 ## 0.3.2 (2019-04-10)
  * Update ERC1820Registry address. ([#26](https://github.com/OpenZeppelin/openzeppelin-test-helpers/pull/26))

README.md

@@ -144,8 +144,12 @@ Same as `inLogs`, but for events emitted in an arbitrary transaction (of hash `t
 ---
 
 
-### makeInterfaceId (interfaces = [])
-Calculates the [EIP 165](https://eips.ethereum.org/EIPS/eip-165) interface ID of a contract, given a series of function signatures.
+### makeInterfaceId
+#### ERC165 (interfaces = [])
+Calculates the [ERC165](https://eips.ethereum.org/EIPS/eip-165) interface ID of a contract, given a series of function signatures.
+
+#### ERC1820 (name)
+Calculates the [ERC1820](https://eips.ethereum.org/EIPS/eip-1820) interface hash of a contract, given its name.
 
 ---
 

src/makeInterfaceId.js

@@ -1,8 +1,8 @@
-const INTERFACE_ID_LENGTH = 4;
+function ERC165 (functionSignatures = []) {
+  const INTERFACE_ID_LENGTH = 4;
 
-function makeInterfaceId (interfaces = []) {
-  const interfaceIdBuffer = interfaces
-    .map(methodSignature => web3.utils.soliditySha3(methodSignature)) // keccak256
+  const interfaceIdBuffer = functionSignatures
+    .map(signature => web3.utils.soliditySha3(signature)) // keccak256
     .map(h =>
       Buffer
         .from(h.substring(2), 'hex')
@@ -18,4 +18,11 @@ function makeInterfaceId (interfaces = []) {
   return `0x${interfaceIdBuffer.toString('hex')}`;
 }
 
-module.exports = makeInterfaceId;
+function ERC1820 (interfaceName) {
+  return web3.utils.soliditySha3(interfaceName); // keccak256
+}
+
+module.exports = {
+  ERC165,
+  ERC1820,
+};

test/src/makeInterfaceId.test.js

@@ -5,15 +5,25 @@ const makeInterfaceId = require('../../src/makeInterfaceId');
 const OwnableInterfaceId = artifacts.require('OwnableInterfaceId');
 
 describe('makeInterfaceId', function () {
-  it('calculates the EIP165 interface id from function signatures', async function () {
-    const calculator = await OwnableInterfaceId.new();
-    const ownableId = await calculator.getInterfaceId();
+  describe('ERC165', function () {
+    it('calculates the interface id from function signatures', async function () {
+      const calculator = await OwnableInterfaceId.new();
+      const ownableId = await calculator.getInterfaceId();
 
-    expect(makeInterfaceId([
-      'owner()',
-      'isOwner()',
-      'renounceOwnership()',
-      'transferOwnership(address)',
-    ])).to.equal(ownableId);
+      expect(makeInterfaceId.ERC165([
+        'owner()',
+        'isOwner()',
+        'renounceOwnership()',
+        'transferOwnership(address)',
+      ])).to.equal(ownableId);
+    });
+  });
+
+  describe('ERC1820', function () {
+    it('calculates the interface hash a from a contract name', async function () {
+      expect(makeInterfaceId.ERC1820('ERC777Token')).to.equal(
+        '0xac7fbab5f54a3ca8194167523c6753bfeb96a445279294b6125b68cce2177054'
+      );
+    });
   });
 });