sequelize-bakery

A test model builder inspired by Django's model-bakery. Allows you to focus your test setup by only specifying fields relevant to your test, and letting the bakery build out everything else.

Problem

You have a deep hierarchy of models, and test setups are tedious because of it.

User.belongsTo(Cohort);
Account.belongsTo(User);
Wallet.belongsTo(Account);

test('should be muddied by needless setup', async () => {
    const cohort = await Cohort.create({ ... }); // irrelevant
    const user = await User.create({ ..., cohort }); // irrelevant
    const account = await Account.create({ ..., user }); // irrelevant
    const wallet = await Wallet.create({ ..., account, balance: 500000 }); // we only care about the balance here

    // ... assertions ...
});

With sequelize-bakery, you can jump straight to target model creation.

const { build } = require('sequelize-bakery');

test('should be clear and to the point', async () => {
    const wallet = await build(Wallet);
    // ... assertions ...
}

If you want to specify any of the fields explicitly:

const wallet = await build(Wallet, { balance: 5000000 } });

If you want to go deep with your specifications:

const wallet = await build(Wallet, { Account: { User: { username: 'overriden' } } });

If you want to explicity supply an existing model, for example, to have two generated models belong to the same parent:

const wallet1 = await build(Wallet);
const wallet2 = await build(Wallet, { Account: wallet1.account });

Nullable fields and default values

Nullable fields will be not be generated, unless they have a defaultValue set, or you specify the fillOptional as true in the third parameter to the build call.

const user = build(User, {}, { fillOptional: true });

In case you want to allow bakery to generate some fields, but not others, you can supply an array of allowed fields instead.

const user = build(User, {}, { fillOptional: ['dateOfBirth'] });

Destroying built models in test teardowns

sequelize-bakery tracks all instances it creates. Calling destroyAllBuilt in test teardowns will automatically destroy all instances built by Sequelize.

const { destroyAllBuilt } = require('sequelize-bakery');

afterEach(async () => {
    await destroyAllBuilt();
});

Overriding generators

In case your models require specialized conversion, you can override the underlying generators. The first parameter is is the type of your column in underlying SQL dialect. (e.g. VARCHAR)

const { overrideGenerator } = require('sequlize-bakery');

overrideGenerator('DECIMAL', () => new CustomBigNumber(faker.datatype.number().toString()));

In addition, if your column has sequelize validation (not constraint!), you can use the same override with the first parameter being the sequelize validator.

overrideGenerator('isEmal', () => `${faker.name.firstName()}@yahoo.com`);

If a column has sequelize validation, the specialized generators take precedence. Some are built in, such as isEmail, isIPv4, etc.

Warning: overrideGenerator overrides both SQL typemap and validator typemap. This overlap behavior is not thoroughly tested and might cause some problems! Be suspect of this if you encounter odd issues while using overrideGenerator.

Limitations

Currently only creating BelongsTo relations, hasMany relations are not yet supported.