chore: Add unit tests to getSwapsDefaultToken

Author: gambinish

ui/selectors/selectors.test.js

@@ -2029,4 +2029,41 @@ describe('#getConnectedSitesList', () => {
       expect(selectors.getSelectedEvmInternalAccount(state)).toBe(undefined);
     });
   });
+
+  describe('getSwapsDefaultToken', () => {
+    it('returns the token object for the current chainId when no overrideChainId is provided', () => {
+      const expectedToken = {
+        symbol: 'ETH',
+        name: 'Ether',
+        address: '0x0000000000000000000000000000000000000000',
+        decimals: 18,
+        balance: '966987986469506564059',
+        string: '966.988',
+        iconUrl: './images/black-eth-logo.svg',
+      };
+
+      const result = selectors.getSwapsDefaultToken(mockState);
+
+      expect(result).toStrictEqual(expectedToken);
+    });
+
+    it('returns the token object for the overridden chainId when overrideChainId is provided', () => {
+      const expectedToken = {
+        symbol: 'POL',
+        name: 'Polygon',
+        address: '0x0000000000000000000000000000000000000000',
+        decimals: 18,
+        balance: '966987986469506564059',
+        string: '966.988',
+        iconUrl: './images/pol-token.svg',
+      };
+
+      const result = selectors.getSwapsDefaultToken(
+        mockState,
+        CHAIN_IDS.POLYGON,
+      );
+
+      expect(result).toStrictEqual(expectedToken);
+    });
+  });
 });