Appsync Mock

It's a library for testing Appsync locally using CDK and AppsyncHelper. The mock tries to create the Appsync environment, so we can run and test functions, resolvers and pipeline resolvers locally on our machine with mocked datasources.

Usage

I am using vitest but jest should be very similar.

vitest.config.ts

import { defineConfig } from 'vitest/config'

export default defineConfig({
  resolve: { 
    alias: { 
      // https://github.com/vitest-dev/vitest/issues/4605
      graphql: "graphql/index.js",

      // replace import.meta.dirname with the cloned repo path
      "@aws-appsync/utils": `${import.meta.dirname}/@aws-appsync-utils`
    } 
  },
});

*.spec.ts

For further references, you can check the tests files in the repo.

let appsync;

beforeAll(async () => {
  const stack = createStack(); // should return yout cdk stack
  appsync = new AppSyncMock(stack, 'MyBackendApi', true);
});

describe('Simple cases', () => {
  it('should return with data from datasource', async () => {
    const resolver = appsync.getResolver('Query.users');
    resolver
      .addDefaultContext({ arguments: { input: { id: 'valid' } } } as Context)
      .addMockDataSource('users', usersDynamoTable);

    const resultContext = await resolver.run();

    expect(resultContext.result).toEqual(
      [{ id: 1, name: 'test', email: '[email protected]', address: '1234 Main St'}]
    );
  });  
});

Mock datasource is a function:

const usersDynamoTable = vi.fn().mockImplementation(({ id }: { id: number }) => {
  const items = [
    { id: 1, name: 'test bar', email: '[email protected]', address: '1234 Main St' },
    { id: 2, name: 'test foo', email: '[email protected]', address: '1235 Sub St' }
  ];

  if (!!id && typeof id === 'number') {
    return { items: [items.find( item => item.id === id )] };
  }

  return { items };
});

Contributing

Feel free to create a PR and extend the @aws-appsync/utils mock any time or just create an issue.