@loopback/repository-tests NPM

@loopback/repository-tests

A test suite verifying functionality of @loopback/repository in a connector-independent way.

Overview

The module provides test-suite factories to define standardized test suite capable of testing any combination of a Repository class and a corresponding connector, for example DefaultCrudRepository with connectors like memory, mysql and mongodb.

Installation

npm install --save @loopback/repository-tests

Basic use

Add the following file to your test suite, and make the following changes:

Replace DefaultCrudRepository with the repository class you want to test.
Replace the string 'memory' with the default export of the connector to use, e.g. require('loopback-connector-mysql').
If your database uses string primary keys (e.g. GUID/UUID), then change idType to 'string'.

import {DefaultCrudRepository} from '@loopback/repository';
import {
  CrudRepositoryCtor,
  crudRepositoryTestSuite,
} from '@loopback/repository-tests';

describe('DefaultCrudRepository + memory connector', () => {
  crudRepositoryTestSuite(
    {
      connector: 'memory',
      // add any database-specific configuration, e.g. credentials & db name
    },
    // Workaround for the following TypeScript error
    //   Type 'DefaultCrudRepository<T, ID, {}>' is not assignable to
    //     type 'EntityCrudRepository<T, ID, Relations>'.
    // See https://github.com/microsoft/TypeScript/issues/31840
    DefaultCrudRepository as CrudRepositoryCtor,
    {
      idType: 'number',
    },
  );
});

Developer guide

Under the hood, the test suite is composed from individual test suite files, e.g. src/__tests__/crud/create-retrieve.suite.ts.

IMPORTANT Keep the size of test files small. Each test file should cover a small & cohesive subset of our features. If a new test does fit the remaining tests in a test file, then move it to a new one.

A test suite file exports a single factory function that's called to define the tests:

export function createRetrieveSuite(
  dataSourceOptions: DataSourceOptions,
  repositoryClass: CrudRepositoryCtor,
  features: CrudFeatures,
) {
  // test code
}

The factory functions can use describe, it and other Mocha API like before/after hooks to define the tests to be executed.

Besides the arguments passed to the factory function, the test context (this provided by Mocha) is initialized with additional properties like this.dataSource (a data-source instance created with dataSourceOptions to be used by tests).

Because accessing Mocha's this in a type-safe way is cumbersome, we have a helper converting this to a named function argument. Example usage:

let repo: EntityCrudRepository<Product, typeof Product.prototype.id>;
before(
  withCrudCtx(async function setupRepository(ctx: CrudTestContext) {
    repo = new repositoryClass(Product, ctx.dataSource);
    await ctx.dataSource.automigrate(Product.name);
  }),
);