Add our first real test

__tests__/main.test.ts

@@ -1,3 +1,61 @@
-describe('TODO - Add a test suite', () => {
-  it('TODO - Add a test', async () => {});
+import * as core from '@actions/core';
+import * as github from '@actions/github';
+import {Octokit} from '@octokit/rest';
+
+import {IssueProcessor, IssueProcessorOptions} from '../src/IssueProcessor';
+
+type Issue = Octokit.IssuesListForRepoResponseItem;
+type IssueLabel = Octokit.IssuesListForRepoResponseItemLabelsItem;
+type IssueList = Octokit.Response<Octokit.IssuesListForRepoResponse>;
+
+const FakeHeaders = {
+  date: 'none',
+  'x-ratelimit-limit': '',
+  'x-ratelimit-remaining': '',
+  'x-ratelimit-reset': '',
+  'x-Octokit-request-id': '',
+  'x-Octokit-media-type': '',
+  link: '',
+  'last-modified': '',
+  etag: '',
+  status: ''
+};
+
+const EmptyIssueList: IssueList = {
+  data: [],
+  status: 200,
+  headers: FakeHeaders,
+
+  *[Symbol.iterator]() {
+    for (let i of this.data) {
+      yield i;
+    }
+  }
+};
+
+test('empty issue list results in 1 operation', async () => {
+  const options: IssueProcessorOptions = {
+    repoToken: 'none',
+    staleIssueMessage: 'This issue is stale',
+    stalePrMessage: 'This PR is stale',
+    daysBeforeStale: 1,
+    daysBeforeClose: 1,
+    staleIssueLabel: 'Stale',
+    exemptIssueLabels: '',
+    stalePrLabel: 'Stale',
+    exemptPrLabels: '',
+    onlyLabels: '',
+    operationsPerRun: 100,
+    debugOnly: true
+  };
+  const processor = new IssueProcessor(options);
+
+  // process our fake issue list
+  const operationsLeft = await processor.processIssues(
+    1,
+    () => new Promise<IssueList>(resolve => resolve(EmptyIssueList))
+  );
+
+  // processing an empty issue list should result in 1 operation
+  expect(operationsLeft).toEqual(99);
 });