test: add erc20 approve test (#2596)

Author: jnsdls

packages/thirdweb/src/extensions/erc20/write/approve.test.ts

@@ -0,0 +1,21 @@
+import { it, expect } from "vitest";
+import { approve } from "./approve.js";
+import { USDC_CONTRACT } from "~test/test-contracts.js";
+import { VITALIK_WALLET } from "~test/addresses.js";
+import { estimateGas } from "../../../transaction/actions/estimate-gas.js";
+
+it.runIf(process.env.TW_SECRET_KEY)(
+  "estimates erc20 approval gas correctly",
+  async () => {
+    const transaction = approve({
+      contract: USDC_CONTRACT,
+      amount: 100,
+      spender: VITALIK_WALLET,
+    });
+    const result = await estimateGas({
+      transaction,
+      from: VITALIK_WALLET,
+    });
+    expect(result).toMatchInlineSnapshot(`55937n`);
+  },
+);