test: src/getCrc32ChecksumAlgorithmFunction.spec.ts

Author: trivikr

packages/middleware-flexible-checksums/src/getCrc32ChecksumAlgorithmFunction.spec.ts

@@ -0,0 +1,48 @@
+import { AwsCrc32 } from "@aws-crypto/crc32";
+import { numToUint8 } from "@aws-crypto/util";
+import { describe, expect, test as it, vi } from "vitest";
+import zlib from "zlib";
+
+import { getCrc32ChecksumAlgorithmFunction } from "./getCrc32ChecksumAlgorithmFunction";
+
+describe(getCrc32ChecksumAlgorithmFunction.name, () => {
+  it("returns AwsCrc32 if zlib.crc32 is undefined", () => {
+    // @ts-expect-error crc32 is defined only for Node.js >=v20.15.0 and >=v22.2.0.
+    zlib.crc32 = undefined;
+    expect(getCrc32ChecksumAlgorithmFunction()).toBe(AwsCrc32);
+  });
+
+  it("returns NodeCrc32 if zlib.crc32 is defined", async () => {
+    const mockData = new Uint8Array([1, 2, 3]);
+    const mockChecksum = 42;
+
+    // @ts-expect-error crc32 is defined only for Node.js >=v20.15.0 and >=v22.2.0.
+    zlib.crc32 = vi
+      .fn()
+      .mockReturnValueOnce(mockChecksum)
+      .mockReturnValueOnce(2 * mockChecksum);
+
+    const crc32Fn = getCrc32ChecksumAlgorithmFunction();
+    expect(crc32Fn).not.toBe(AwsCrc32);
+
+    // @ts-expect-error crc32 is defined only for Node.js >=v20.15.0 and >=v22.2.0.
+    expect(zlib.crc32).not.toHaveBeenCalled();
+    const crc32 = new crc32Fn();
+    // @ts-expect-error crc32 is defined only for Node.js >=v20.15.0 and >=v22.2.0.
+    expect(zlib.crc32).not.toHaveBeenCalled();
+    expect(await crc32.digest()).toEqual(numToUint8(0));
+
+    crc32.update(mockData);
+    // @ts-expect-error crc32 is defined only for Node.js >=v20.15.0 and >=v22.2.0.
+    expect(zlib.crc32).toHaveBeenCalledWith(mockData, 0);
+    expect(await crc32.digest()).toEqual(numToUint8(mockChecksum));
+
+    crc32.update(mockData);
+    // @ts-expect-error crc32 is defined only for Node.js >=v20.15.0 and >=v22.2.0.
+    expect(zlib.crc32).toHaveBeenCalledWith(mockData, mockChecksum);
+    expect(await crc32.digest()).toEqual(numToUint8(2 * mockChecksum));
+
+    crc32.reset();
+    expect(await crc32.digest()).toEqual(numToUint8(0));
+  });
+});

packages/middleware-flexible-checksums/src/getCrc32ChecksumAlgorithmFunction.ts

@@ -4,7 +4,7 @@ import { Checksum } from "@smithy/types";
 import zlib from "zlib";
 
 export const getCrc32ChecksumAlgorithmFunction = () => {
-  // @ts-expect-error crc32 is defined only for Node.js >v20.15.0+ and >v22.2.0+.
+  // @ts-expect-error crc32 is defined only for Node.js >=v20.15.0 and >=v22.2.0.
   if (typeof zlib.crc32 === "undefined") {
     return AwsCrc32;
   }
@@ -13,7 +13,7 @@ export const getCrc32ChecksumAlgorithmFunction = () => {
     private checksum = 0;
 
     update(data: Uint8Array) {
-      // @ts-expect-error crc32 is defined only for Node.js >v20.15.0+ and >v22.2.0+.
+      // @ts-expect-error crc32 is defined only for Node.js >=v20.15.0 and >=v22.2.0.
       this.checksum = zlib.crc32(data, this.checksum);
     }