Initial support for job queue

ts/test-node/jobs/JobError_test.ts

@@ -0,0 +1,33 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { assert } from 'chai';
+
+import { JobError } from '../../jobs/JobError';
+
+describe('JobError', () => {
+  it('stores the provided argument as a property', () => {
+    const fakeError = new Error('uh oh');
+    const jobError1 = new JobError(fakeError);
+    assert.strictEqual(jobError1.lastErrorThrownByJob, fakeError);
+
+    const jobError2 = new JobError(123);
+    assert.strictEqual(jobError2.lastErrorThrownByJob, 123);
+  });
+
+  it('if passed an Error, augments its `message`', () => {
+    const fakeError = new Error('uh oh');
+    const jobError = new JobError(fakeError);
+
+    assert.strictEqual(jobError.message, 'Job failed. Last error: uh oh');
+  });
+
+  it('if passed a non-Error, stringifies it', () => {
+    const jobError = new JobError({ foo: 'bar' });
+
+    assert.strictEqual(
+      jobError.message,
+      'Job failed. Last error: {"foo":"bar"}'
+    );
+  });
+});