feat: balancer v2 buy support for specific pools

src/dex/balancer-v2/balancer-v2-e2e.test.ts

@@ -11,7 +11,6 @@ import { ContractMethod, Network, SwapSide } from '../../constants';
 import { StaticJsonRpcProvider } from '@ethersproject/providers';
 
 import { generateConfig } from '../../config';
-import { DirectMethodsV6 } from './constants';
 
 jest.setTimeout(50 * 1000);
 
@@ -543,6 +542,62 @@ describe('BalancerV2 E2E', () => {
       );
     });
 
+    describe('GHO -> USDT buy', () => {
+      const sideToContractMethods = new Map([
+        [
+          SwapSide.BUY,
+          [
+            ContractMethod.swapExactAmountOutOnBalancerV2,
+            ContractMethod.swapExactAmountOut,
+          ],
+        ],
+      ]);
+
+      const pairs: { name: string; amount: string }[][] = [
+        [
+          { name: 'GHO', amount: '81530002926' },
+          { name: 'USDT', amount: '82245407358961750602330' },
+        ],
+      ];
+
+      sideToContractMethods.forEach((contractMethods, side) =>
+        describe(`${side}`, () => {
+          contractMethods.forEach((contractMethod: ContractMethod) => {
+            pairs.forEach(pair => {
+              describe(`${contractMethod}`, () => {
+                it(`${pair[0].name} -> ${pair[1].name}`, async () => {
+                  await testE2E(
+                    tokens[pair[0].name],
+                    tokens[pair[1].name],
+                    holders[pair[0].name],
+                    pair[0].amount,
+                    side,
+                    dexKey,
+                    contractMethod,
+                    network,
+                    provider,
+                  );
+                });
+                it(`${pair[1].name} -> ${pair[0].name}`, async () => {
+                  await testE2E(
+                    tokens[pair[1].name],
+                    tokens[pair[0].name],
+                    holders[pair[1].name],
+                    pair[1].amount,
+                    side,
+                    dexKey,
+                    contractMethod,
+                    network,
+                    provider,
+                  );
+                });
+              });
+            });
+          });
+        }),
+      );
+    });
+
     //daniel: BPT swaps are currently not supported, we've refactored to focus on mainToken paths
     /*it('MAIN TOKEN -> BPT, LinearPool', async () => {
         // Linear Pools allow swaps between main token (i.e. USDT) and pools BPT

src/dex/balancer-v2/balancer-v2.ts

@@ -268,6 +268,12 @@ export class BalancerV2EventPool extends StatefulEventSubscriber<PoolStateMap> {
     BalancerPoolTypes.GyroE,
   ]);
 
+  buySupportedPoolAddresses: Partial<Record<number, Set<Address>>> = {
+    [Network.MAINNET]: new Set([
+      '0x8353157092ed8be69a9df8f95af097bbf33cb2af', // ComposableStable USDC - USDT - GHO
+    ]),
+  };
+
   eventSupportedPoolTypes: BalancerPoolTypes[] = [
     BalancerPoolTypes.Stable,
     BalancerPoolTypes.Weighted,
@@ -511,7 +517,12 @@ export class BalancerV2EventPool extends StatefulEventSubscriber<PoolStateMap> {
 
     if (
       side === SwapSide.BUY &&
-      !this.buySupportedPoolTypes.has(subgraphPool.poolType)
+      !(
+        this.buySupportedPoolTypes.has(subgraphPool.poolType) ||
+        this.buySupportedPoolAddresses[this.network]?.has(
+          subgraphPool.address.toLowerCase(),
+        )
+      )
     ) {
       return null;
     }