Add legacy client integration test and README.md section

Author: fern-api[bot]

README.md

@@ -53,6 +53,69 @@ await client.payments.create({
 });
 ```
 
+## Legacy SDK
+
+While the new SDK has a lot of improvements, we at Square understand that it takes time to upgrade when there are breaking changes.
+To make the migration easier, the new SDK also exports the legacy SDK as `square/legacy`. Here's an example of how you can use the
+legacy SDK alongside the new SDK inside a single file:
+
+```typescript
+import { randomUUID } from "crypto";
+import { Square, SquareClient } from "square";
+import { Client } from "square/legacy";
+
+const client = new SquareClient({
+  token: process.env.SQUARE_ACCESS_TOKEN,
+});
+
+const legacyClient = new Client({
+  bearerAuthCredentials: {
+    accessToken: process.env.SQUARE_ACCESS_TOKEN!,
+  },
+});
+
+async function getLocation(): Promise<Square.Location> {
+  return (
+    await client.locations.get({
+      locationId: "YOUR_LOCATION_ID",
+    })
+  ).location!;
+}
+
+async function createOrder() {
+  const location = await getLocation();
+  await legacyClient.ordersApi.createOrder({
+    idempotencyKey: randomUUID(),
+    order: {
+      locationId: location.id!,
+      lineItems: [
+        {
+          name: "New Item",
+          quantity: "1",
+          basePriceMoney: {
+            amount: BigInt(100),
+            currency: "USD",
+          },
+        },
+      ],
+    },
+  });
+}
+
+createOrder();
+```
+
+We recommend migrating to the new SDK using the following steps:
+
+1. Upgrade the NPM module to `^40.0.0`
+2. Search and replace all requires and imports from `"square"` to `"square/legacy"`
+
+- For required, replace `require("square")` with `require("square/legacy")`
+- For imports, replace `from "square"` with `from "square/legacy"`
+- For dynamic imports, replace `import("square")` with `import("square/legacy")`
+
+3. Gradually move over to use the new SDK by importing it from the `"square"` import.
+
 ## Request And Response Types
 
 The SDK exports all request and response types as TypeScript interfaces. Simply import them with the

tests/integration/helpers.ts

@@ -1,6 +1,7 @@
 import { randomUUID } from "crypto";
 import { readFile } from "fs/promises";
 import path from "path";
+import { Client, Environment } from "../../legacy/exports";
 import { Square, SquareClient, SquareEnvironment } from "../../src";
 
 export const createClient = (): SquareClient => {
@@ -14,6 +15,19 @@ export const createClient = (): SquareClient => {
     });
 };
 
+export const createLegacyClient = (): Client => {
+    const token = process.env.TEST_SQUARE_TOKEN;
+    if (!token) {
+        throw new Error("TEST_SQUARE_TOKEN is not set");
+    }
+    return new Client({
+        environment: Environment.Sandbox,
+        bearerAuthCredentials: {
+            accessToken: token,
+        },
+    });
+};
+
 export function newTestUuid(): string {
     return randomUUID();
 }

tests/integration/legacy.test.ts

@@ -0,0 +1,13 @@
+import { Client } from "../../legacy/exports";
+import { createLegacyClient } from "./helpers";
+
+describe("Legacy SDK", () => {
+    const legacyClient: Client = createLegacyClient();
+
+    it("should list locations", async () => {
+        const response = await legacyClient.locationsApi.listLocations();
+
+        expect(response.result.locations).toBeDefined();
+        expect(response.result.locations?.length).toBeGreaterThan(0);
+    });
+});