Added some basic tests for stackoverflow backend plugin

Signed-off-by: Scott Guymer <scott.guymer@philips.com>

plugins/stack-overflow-backend/package.json

@@ -32,13 +32,19 @@
     "clean": "backstage-cli package clean"
   },
   "dependencies": {
-    "@backstage/cli": "workspace:^",
+    "@backstage/backend-common": "workspace:^",
     "@backstage/config": "workspace:^",
     "@backstage/plugin-search-common": "workspace:^",
     "node-fetch": "^2.6.7",
     "qs": "^6.9.4",
     "winston": "^3.2.1"
   },
+  "devDependencies": {
+    "@backstage/backend-test-utils": "workspace:^",
+    "@backstage/cli": "workspace:^",
+    "@backstage/plugin-search-backend-node": "workspace:^",
+    "msw": "^0.49.0"
+  },
   "files": [
     "dist",
     "config.d.ts"

plugins/stack-overflow-backend/src/search/StackOverflowQuestionsCollatorFactory.test.ts

@@ -0,0 +1,151 @@
+/*
+ * Copyright 2022 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import { getVoidLogger } from '@backstage/backend-common';
+import {
+  StackOverflowQuestionsCollatorFactory,
+  StackOverflowQuestionsCollatorFactoryOptions,
+} from './StackOverflowQuestionsCollatorFactory';
+import { setupRequestMockHandlers } from '@backstage/backend-test-utils';
+import { TestPipeline } from '@backstage/plugin-search-backend-node';
+import { ConfigReader } from '@backstage/config';
+import { Readable } from 'stream';
+import { setupServer } from 'msw/node';
+import { rest } from 'msw';
+
+const logger = getVoidLogger();
+
+const mockQuestion = {
+  items: [
+    {
+      tags: ['backstage'],
+      owner: {
+        display_name: 'The Riddler',
+      },
+      answer_count: 1,
+      link: 'https://stack.overflow.local/questions/2911',
+      title: 'This is the first question',
+    },
+  ],
+  has_more: false,
+};
+
+const mockOverrideQuestion = {
+  items: [
+    {
+      tags: ['backstage'],
+      owner: {
+        display_name: 'The Riddler',
+      },
+      answer_count: 1,
+      link: 'https://stack.overflow.local/questions/1',
+      title: 'This is the first question',
+    },
+    {
+      tags: ['backstage'],
+      owner: {
+        display_name: 'The Riddler',
+      },
+      answer_count: 1,
+      link: 'https://stack.overflow.local/questions/2',
+      title: 'this is another question',
+    },
+  ],
+  has_more: false,
+};
+
+describe('StackOverflowQuestionsCollatorFactory', () => {
+  const config = new ConfigReader({
+    stackoverflow: {
+      baseUrl: 'http://stack.overflow.local',
+    },
+  });
+
+  const defaultOptions: StackOverflowQuestionsCollatorFactoryOptions = {
+    logger,
+    requestParams: {
+      tagged: ['developer-portal'],
+      pagesize: 100,
+      order: 'desc',
+      sort: 'activity',
+    },
+  };
+
+  it('has expected type', () => {
+    const factory = StackOverflowQuestionsCollatorFactory.fromConfig(
+      config,
+      defaultOptions,
+    );
+    expect(factory.type).toBe('stack-overflow');
+  });
+
+  describe('getCollator', () => {
+    const worker = setupServer();
+    setupRequestMockHandlers(worker);
+
+    afterEach(async () => {
+      worker.resetHandlers();
+    });
+
+    afterAll(async () => {
+      worker.close();
+    });
+
+    it('returns a readable stream', async () => {
+      const factory = StackOverflowQuestionsCollatorFactory.fromConfig(
+        config,
+        defaultOptions,
+      );
+      const collator = await factory.getCollator();
+      expect(collator).toBeInstanceOf(Readable);
+    });
+
+    it('fetches from the configured endpoint', async () => {
+      worker.use(
+        rest.get('http://stack.overflow.local/questions', (_, res, ctx) =>
+          res(ctx.status(200), ctx.json(mockQuestion)),
+        ),
+      );
+      const factory = StackOverflowQuestionsCollatorFactory.fromConfig(
+        config,
+        defaultOptions,
+      );
+      const collator = await factory.getCollator();
+      const pipeline = TestPipeline.fromCollator(collator);
+      const { documents } = await pipeline.execute();
+
+      expect(documents).toHaveLength(mockQuestion.items.length);
+    });
+
+    it('fetches from the overridden endpoint', async () => {
+      worker.use(
+        rest.get('http://stack.overflow.override/questions', (_, res, ctx) =>
+          res(ctx.status(200), ctx.json(mockOverrideQuestion)),
+        ),
+      );
+      const factory = StackOverflowQuestionsCollatorFactory.fromConfig(config, {
+        logger,
+        baseUrl: 'http://stack.overflow.override',
+        requestParams: defaultOptions.requestParams,
+      });
+      const collator = await factory.getCollator();
+
+      const pipeline = TestPipeline.fromCollator(collator);
+      const { documents } = await pipeline.execute();
+
+      expect(documents).toHaveLength(mockOverrideQuestion.items.length);
+    });
+  });
+});