Reorganize test cases

ts/test-node/util/explodePromise_test.ts

@@ -0,0 +1,24 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { assert } from 'chai';
+
+import { explodePromise } from '../../util/explodePromise';
+
+describe('explodePromise', () => {
+  it('resolves the promise', async () => {
+    const { promise, resolve } = explodePromise<number>();
+
+    resolve(42);
+
+    assert.strictEqual(await promise, 42);
+  });
+
+  it('rejects the promise', async () => {
+    const { promise, reject } = explodePromise<number>();
+
+    reject(new Error('rejected'));
+
+    await assert.isRejected(promise, 'rejected');
+  });
+});