Add unit test against current master

packages/beacon-state-transition/test/perf/shuffle/shuffle.perf.ts

@@ -9,12 +9,8 @@ import {BenchmarkRunner} from "../runner";
 
 // eslint-disable-next-line @typescript-eslint/no-floating-promises
 (async function () {
-  const config = {
-    params: {
-      // eslint-disable-next-line @typescript-eslint/naming-convention
-      SHUFFLE_ROUND_COUNT: 90,
-    },
-  } as IBeaconConfig;
+  // eslint-disable-next-line @typescript-eslint/naming-convention
+  const config = {params: {SHUFFLE_ROUND_COUNT: 90}} as IBeaconConfig;
   const seed = new Uint8Array([42, 32]);
 
   const runner = new BenchmarkRunner("shuffle list", {

packages/beacon-state-transition/test/unit/stateTransition/util/shuffle.test.ts

@@ -0,0 +1,34 @@
+import {IBeaconConfig} from "@chainsafe/lodestar-config";
+import {expect} from "chai";
+import {unshuffleList} from "../../../../src";
+
+describe("util / shuffle", () => {
+  const testCases: {
+    id: string;
+    input: number[];
+    res: number[];
+  }[] = [
+    // Values from `unshuffleList()` at commit https://github.com/ChainSafe/lodestar/commit/ec065635ca7da7f3788da018bd68c4900f0427d2
+    {
+      id: "8 elements",
+      input: [0, 1, 2, 3, 4, 5, 6, 7],
+      res: [6, 3, 4, 0, 1, 5, 7, 2],
+    },
+    {
+      id: "16 elements",
+      input: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15],
+      res: [8, 4, 11, 7, 10, 6, 0, 3, 15, 12, 5, 14, 1, 9, 13, 2],
+    },
+  ];
+
+  // eslint-disable-next-line @typescript-eslint/naming-convention
+  const config = {params: {SHUFFLE_ROUND_COUNT: 90}} as IBeaconConfig;
+  const seed = new Uint8Array([42, 32]);
+
+  for (const {id, input, res} of testCases) {
+    it(id, () => {
+      unshuffleList(config, input, seed);
+      expect(input).to.deep.equal(res);
+    });
+  }
+});