Merge pull request #74 from ScottLogic/SDE-170-test-scheduled-daily-d…

…igests

SDE-170: Scheduled Daily Digests Test

.circleci/config.yml

@@ -41,6 +41,9 @@ jobs:
       - run:
           name: Run ESLint
           command: npm run lint
+      - run:
+          name: Run Unit Tests
+          command: npm test
   serverless-deploy:
     docker:
       - image: circleci/node:10.15.1

.gitignore

@@ -43,3 +43,6 @@ circleci.exe
 
 # Env directories
 env/
+
+# VS Code Config Directory
+.vscode/

functions/scheduledDailyDigests.js

@@ -1,11 +1,10 @@
 import { DynamoDB, Lambda } from 'aws-sdk';
 
-const dynamoDbDocumentClient = new DynamoDB.DocumentClient();
-const lambda = new Lambda();
-
-const { SUBSCRIPTIONS_TABLE: TableName, USER_DIGEST_LAMBDA_NAME: FunctionName } = process.env;
-
 export const handler = async () => {
+  const { SUBSCRIPTIONS_TABLE: TableName, USER_DIGEST_LAMBDA_NAME: FunctionName } = process.env;
+  const dynamoDbDocumentClient = new DynamoDB.DocumentClient();
+  const lambda = new Lambda();
+
   const scanParams = { TableName };
   const { Items } = await dynamoDbDocumentClient.scan(scanParams).promise();
   await Promise.all(

tests/scheduledDailyDigests.test.js

@@ -0,0 +1,40 @@
+import { DynamoDB, Lambda } from 'aws-sdk';
+import { handler } from '../functions/scheduledDailyDigests';
+
+jest.mock('aws-sdk');
+
+const subscriptionsTableData = {
+  Items: [
+    { userId: 1, subscriptions: [] },
+    { userId: 2, subscriptions: ['test'] },
+    { userId: 3, subscriptions: ['test1', 'test2'] }
+  ]
+};
+
+const mockDynamoDbScan = {
+  promise: jest.fn()
+};
+
+const mockLambdaInvoke = {
+  promise: jest.fn()
+};
+
+DynamoDB.DocumentClient.mockImplementation(() => ({ scan: () => mockDynamoDbScan }));
+
+Lambda.mockImplementation(() => ({ invoke: () => mockLambdaInvoke }));
+
+describe('scheduledDailyDigests function', () => {
+  beforeAll(() => {
+    process.env = Object.assign(process.env, {
+      SUBSCRIPTIONS_TABLE: 'subscriptions',
+      USER_DIGEST_LAMBDA_NAME: 'calculateUserDailyDigest'
+    });
+  });
+
+  it('invokes calculateUserDailyDigest for each user with at least one subscription', async () => {
+    mockDynamoDbScan.promise.mockResolvedValue(subscriptionsTableData);
+    mockLambdaInvoke.promise.mockResolvedValue();
+    await handler();
+    expect(mockLambdaInvoke.promise).toHaveBeenCalledTimes(2);
+  });
+});