fix!(keyring-eth-ledger-bridge): change addAccounts to return new a…

…ccounts only (#63)

<!--
Thanks for your contribution! Take a moment to answer these questions so
that reviewers have the information they need to properly understand
your changes:

* What is the current state of things and why does it need to change?
* What is the solution your changes offer and how does it work?

Are there any issues or other links reviewers should consult to
understand this pull request better? For instance:

* Fixes #12345
* See: #67890
-->

The `addAccounts` method should return newly create accounts, instead of
all the accounts present in the keyring.

Related: MetaMask/accounts-planning#615

## Examples

<!--
Are there any examples of this change being used in another repository?

When considering changes to the MetaMask module template, it's strongly
preferred that the change be experimented with in another repository
first. This gives reviewers a better sense of how the change works,
making it less likely the change will need to be reverted or adjusted
later.
-->

packages/keyring-eth-ledger-bridge/jest.config.js

@@ -25,8 +25,8 @@ module.exports = merge(baseConfig, {
     global: {
       branches: 90.64,
       functions: 95.95,
-      lines: 93.02,
-      statements: 93.09,
+      lines: 94.76,
+      statements: 94.81,
     },
   },
 });

packages/keyring-eth-ledger-bridge/src/ledger-keyring.test.ts

@@ -388,16 +388,26 @@ describe('LedgerKeyring', function () {
       describe('with a numeric argument', function () {
         it('returns that number of accounts', async function () {
           keyring.setAccountToUnlock(0);
-          const accounts = await keyring.addAccounts(5);
-          expect(accounts).toHaveLength(5);
+          const firstBatch = await keyring.addAccounts(3);
+          keyring.setAccountToUnlock(3);
+          const secondBatch = await keyring.addAccounts(2);
+
+          expect(firstBatch).toHaveLength(3);
+          expect(secondBatch).toHaveLength(2);
         });
 
         it('returns the expected accounts', async function () {
           keyring.setAccountToUnlock(0);
-          const accounts = await keyring.addAccounts(3);
-          expect(accounts[0]).toBe(fakeAccounts[0]);
-          expect(accounts[1]).toBe(fakeAccounts[1]);
-          expect(accounts[2]).toBe(fakeAccounts[2]);
+          const firstBatch = await keyring.addAccounts(3);
+          keyring.setAccountToUnlock(3);
+          const secondBatch = await keyring.addAccounts(2);
+
+          expect(firstBatch).toStrictEqual([
+            fakeAccounts[0],
+            fakeAccounts[1],
+            fakeAccounts[2],
+          ]);
+          expect(secondBatch).toStrictEqual([fakeAccounts[3], fakeAccounts[4]]);
         });
       });
 
@@ -425,13 +435,13 @@ describe('LedgerKeyring', function () {
       describe('when called multiple times', function () {
         it('does not remove existing accounts', async function () {
           keyring.setAccountToUnlock(0);
-          await keyring.addAccounts(1);
+          const firstBatch = await keyring.addAccounts(1);
           keyring.setAccountToUnlock(1);
-          const accounts = await keyring.addAccounts(1);
+          const secondBatch = await keyring.addAccounts(1);
 
-          expect(accounts).toHaveLength(2);
-          expect(accounts[0]).toBe(fakeAccounts[0]);
-          expect(accounts[1]).toBe(fakeAccounts[1]);
+          expect(await keyring.getAccounts()).toHaveLength(2);
+          expect(firstBatch).toStrictEqual([fakeAccounts[0]]);
+          expect(secondBatch).toStrictEqual([fakeAccounts[1]]);
         });
       });
     });

packages/keyring-eth-ledger-bridge/src/ledger-keyring.ts

@@ -242,6 +242,7 @@ export class LedgerKeyring extends EventEmitter {
         .then(async (_) => {
           const from = this.unlockedAccount;
           const to = from + amount;
+          const newAccounts: string[] = [];
           for (let i = from; i < to; i++) {
             const path = this.#getPathForIndex(i);
             let address;
@@ -260,10 +261,11 @@ export class LedgerKeyring extends EventEmitter {
 
             if (!this.accounts.includes(address)) {
               this.accounts = [...this.accounts, address];
+              newAccounts.push(address);
             }
             this.page = 0;
           }
-          resolve(this.accounts.slice());
+          resolve(newAccounts);
         })
         .catch(reject);
     });