adding ERC721 detection to TokensController

package.json

@@ -51,6 +51,7 @@
     "eth-sig-util": "^3.0.0",
     "ethereumjs-util": "^7.0.10",
     "ethereumjs-wallet": "^1.0.1",
+    "ethers": "^5.4.1",
     "ethjs-unit": "^0.1.6",
     "ethjs-util": "^0.1.6",
     "human-standard-collectible-abi": "^1.0.2",

src/assets/AssetsDetectionController.test.ts

@@ -255,6 +255,9 @@ describe('AssetsDetectionController', () => {
           },
         ],
       });
+    stub(tokensController, '_detectIsERC721').callsFake(() =>
+      Promise.resolve(false),
+    );
   });
 
   afterEach(() => {
@@ -580,6 +583,7 @@ describe('AssetsDetectionController', () => {
         symbol: 'GNO',
         decimals: 18,
         image: undefined,
+        isERC721: false,
       },
     ]);
   });
@@ -595,6 +599,7 @@ describe('AssetsDetectionController', () => {
         decimals: 18,
         image: undefined,
         symbol: 'GNO',
+        isERC721: false,
       },
     ]);
     getBalancesInSingleCall.resolves({
@@ -607,12 +612,14 @@ describe('AssetsDetectionController', () => {
         decimals: 18,
         image: undefined,
         symbol: 'GNO',
+        isERC721: false,
       },
       {
         address: '0x514910771AF9Ca656af840dff83E8264EcF986CA',
         symbol: 'LINK',
         decimals: 18,
         image: undefined,
+        isERC721: false,
       },
     ]);
   });
@@ -667,6 +674,9 @@ describe('AssetsDetectionController', () => {
   });
 
   it('should subscribe to new sibling detecting assets when account changes', async () => {
+    stub(tokensController, '_instantiateNewEthersProvider').callsFake(
+      () => null,
+    );
     const firstNetworkType = 'rinkeby';
     const secondNetworkType = 'mainnet';
     const firstAddress = '0x123';

src/assets/TokenBalancesController.test.ts

@@ -182,21 +182,28 @@ describe('TokenBalancesController', () => {
     const assetsContract = new AssetsContractController();
     const network = new NetworkController();
     const preferences = new PreferencesController();
-    const assets = new TokensController({
+    const tokensController = new TokensController({
       onPreferencesStateChange: (listener) => preferences.subscribe(listener),
       onNetworkStateChange: (listener) => network.subscribe(listener),
     });
+
+    const supportsInterfaceStub = stub().returns(Promise.resolve(false));
+
+    stub(tokensController, '_createEthersContract').callsFake(() =>
+      Promise.resolve({ supportsInterface: supportsInterfaceStub }),
+    );
+
     const tokenBalances = new TokenBalancesController(
       {
-        onTokensStateChange: (listener) => assets.subscribe(listener),
+        onTokensStateChange: (listener) => tokensController.subscribe(listener),
         getSelectedAddress: () => preferences.state.selectedAddress,
         getBalanceOf: assetsContract.getBalanceOf.bind(assetsContract),
       },
       { interval: 1337 },
     );
     const updateBalances = sandbox.stub(tokenBalances, 'updateBalances');
-    await assets.addToken('0x00', 'FOO', 18);
-    const { tokens } = assets.state;
+    await tokensController.addToken('0x00', 'FOO', 18);
+    const { tokens } = tokensController.state;
     const found = tokens.filter((token: Token) => token.address === '0x00');
     expect(found.length > 0).toBe(true);
     expect(updateBalances.called).toBe(true);

src/assets/TokenRatesController.ts

@@ -45,6 +45,7 @@ export interface Token {
   symbol: string;
   image?: string;
   balanceError?: Error | null;
+  isERC721?: boolean;
 }
 
 /**