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Tests with Jest and TypeORM

Caio Lucas on June 14, 2020

Hello Everyone! So, today I'll show you how to configure your code to make tests with TypeORM and Jest. Modules First thing ...
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morcegon_22 profile image
Renan Andrade •

Hello dude!
First of all, thank you by the great article, it help me a lot.
I've noticed that in the clear function you put an await function inside a forEach iterator, but in this case the promise will not work properly.
I solve this issue using the map instead the forEach and placing the map result inside a Promise.all(). This works great to me.

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Sadra Isapanah Amlashi • • Edited

Can you put your example here please?

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Samrith Shankar •

Here you go:

const entityDeletionPromises = entities.map((entity) => async() => {
  const repository = connection.getRepository(entity.name);
  await repository.query(`DELETE FROM ${entity.tableName}`);
});
await Promise.all(entityDeletionPromises);
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jack-biles-technology • • Edited

I'm currently using typeorm 0.2.31 and they allow for repo.clear() to truncate / drop the table

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Kent Bull •

I ended up putting a separate call to testConn.create() in a module called my Jest Global setup hook so I could instruct Jest to refresh the database at the start of the test run by dropping the schema and recreating it from migrations by passing in dropSchema: true

Example:

async create(dropSchema: boolean) {
    return await createConnection({
      name: 'default',
      type: 'postgres',
      host: 'localhost',
      port: 5432,
      username: 'postgres',
      password: 'postgres',
      database: 'mydb_localtest',
      dropSchema: dropSchema,
      migrationsRun: dropSchema,
      entities: [__dirname + '/../entity/*.*'],
      migrations: [__dirname + '/../migration/*.*'],
    });
  },
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Then, if using TypeScript, add globalSetup and globalTeardown to your jest.config.js file like so (at bottom):

module.exports = {
  globals: {
    'ts-jest': {
      diagnostics: false,
      isolatedModules: true,
    },
  },
  preset: 'ts-jest',
  testEnvironment: 'node',
  testMatch: [
    "**/__tests__/**/*.spec.ts"
  ],
  setupFiles: ['./src/helpers/envSetup.ts'],
  roots: ['./__tests__/'],
  globalSetup: "./__tests__/globalSetup.js",
  globalTeardown: "./__tests__/globalTeardown.js"
};
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Then, in globalSetup.js you can call your TypeScript setup module by doing the following:

require("ts-node/register");
// using WillAvudim's solution: https://github.com/facebook/jest/issues/5164#issuecomment-376006851

const  { setup } = require( '../src/testing/MyTestLifecycle');
module.exports = async function globalSetup() {
  await setup();
  return null;
}
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The MyTestLifecycle module (in Typescript) just calls testConn.create(true) so that the schema is dropped at the start of all my tests and then re-created by running the migrations:

import { testConn } from './testConn';

export async function setup() {
  await testConn.create(true);
}
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Let me know when this is useful you!

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Hantsy Bai •

I do not want to use a real database connection in the tests, how to test my custom Repository.
stackoverflow.com/questions/675802...

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Hantsy Bai • • Edited 
 await repository.query(`DELETE FROM ${entity.tableName}`);
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This will be a problem when you set the relations between tables.

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oxilor profile image
oxilor • • Edited

You can do the following way:

afterEach(async () => {
  const entities = connection.entityMetadatas;
  for (const entity of entities) {
    const repository = connection.getRepository(entity.name);
    const schemaPrefix = entity.schema ? `${entity.schema}.` : '';
    await repository.query(
      `TRUNCATE ${schemaPrefix}${entity.tableName} RESTART IDENTITY CASCADE`
    );
  }
});
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The TypeORM also has the synchronize method, so you can simplify this code:

afterEach(async () => {
  await connection.synchronize(true);
});
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true means that TypeORM will drop all tables before syncing.

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Kent Bull •

You can just drop the schema and recreate it from migrations. See my other response.

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Alex Rodrigues Moreira •

Valeu mano, vc me ajudou muito agora.

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NipunaC95 •

This is a wrong practice. unit tests should not use external resources like databases. In the other hand integration tests use api calls and check the whole functionality of the api. but whet you implemented here is somewhat in between that

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Lucas Hang • • Edited

Man, that's beautiful.
Just a thing about the connection.clear inside beforeEach(), maybe it's better put it inside afterEach() and then another clear() inside afterAll().

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ezzabuzaid profile image
ezzabuzaid •

Thank You!

You can use global setup and teardown files that can run the create and clear functions without repeating them in each file

jestjs.io/docs/en/configuration#gl...

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Paulo Henrique •

OMG, you saved my life!! Thx! Congrats by the awesome article

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Hiroki Takahashi •

Thank you for this article.
I guess it's necessary to use "--runInBand" flag when running tests with this setting. Otherwise, DB connection may be closed before executing all test files