Lambda stubs

Supports unit testing (or other use cases) in AWS lambda functions by providing functions to generate event and context stubs.

API Gateway

Authorizer

Generates API Gateway authorizer stub.

import { apiGatewayAuthorizerEvent } from 'lambda-stubs';

const actualResult = await handler(apiGatewayAuthorizerEvent());

expect(actualResult).toMatchSnapshot();

Proxy event handler

import { apiGatewayProxyEvent, apiGatewayProxyContext } from 'lambda-stubs';

const actualResult = await handler(
  apiGatewayProxyEvent({
    /* Commonly useful params --------------------- */
    body: {
      text: 'foo bar',
    },
    resourcePath: 'teams/{teamId}/members',
    pathParameters: {
      teamId: '5',
    },
    headers: {
      'Content-Type': 'application/json',
      foo: 'bar',
    },
    /* Rarely useful params ----------------------- */
    // apiId: 'my-api',
    // sourceIp: '123.123.123.123',
    // stage: 'mock-stage',
    // userAgent: 'MockApi/1.0.0',
    // authorizationHeaderGenerator: () => 'my-secret-header',
    // resourceId: 'asdfgh',
    // authorizer: {
    //   principalId: 'mock-principal',
    //   integrationLatency: 123,
    // },
  }),
  apiGatewayProxyContext({
    functionName: 'My function',
    memoryLimitInMB: 128,
  }),
  jest.fn,
);

expect(actualResult).toMatchSnapshot();

SNS

import { snsEvent, apiGatewayProxyContext } from 'lambda-stubs';

const actualResult = await handler(
  snsEvent({
    /* Occasionally useful (but optional) params ----- */
    Subject: 'EXAMPLE-SUBJECT',
    Message: 'EXAMPLE-MESSAGE',
    TopicArn: 'arn:aws:sns:eu-west-1-1:123456789012:ExampleTopic',
    EventSubscriptionArn: 'arn:aws:sns:us-east-1:123456789012:ExampleTopic',
    MessageAttributes: {
      Test: {
        Type: 'String',
        Value: 'TestString',
      },
      TestBinary: {
        Type: 'Binary',
        Value: 'TestBinary',
      },
    },
    MessageId: uuidv4(),
    Timestamp: new Date().toISOString(),
  }),
  apiGatewayProxyContext({
    functionName: 'My function',
    memoryLimitInMB: 256,
  }),
  jest.fn,
);

expect(actualResult).toMatchSnapshot();

EventBridge

Scheduled Event

import { eventBridgeEvent, apiGatewayProxyContext } from 'lambda-stubs';

const actualResult = await handler(
  eventBridgeEvent({
    /* Occasionally useful (but optional) params ----- */
    version: '1',
    source: 'aws.events',
    accountId: '123456789012',
    time: new Date().toISOString(),
    region: 'eu-west-1',
    resources: [`arn:aws:events:eu-west-1:123456789012:rule/ExampleRule`],
    detail: {},
  }),
  apiGatewayProxyContext({
    functionName: 'My function',
    memoryLimitInMB: 256,
  }),
  jest.fn,
);

expect(actualResult).toMatchSnapshot();