jest-test-utils v1.7.1

jest-test-utils

Utility functions for use in tests using jest.

Installation

npm install --save-dev jest-test-utils

Usage

Setup jest

Add this to your jest config to extend jest expect with SQL statement matchers:

{
    "setupFilesAfterEnv": ["node_modules/jest-test-utils/dist/jest/sqlStatementMatchers.js"]
}

If you want to mock the i18next module, you can also add this to your jest config:

{
    "setupFilesAfterEnv": ["node_modules/jest-test-utils/dist/jest/mockI18next.js"]
}

After this mock is applied i18next.t() no longer returns the translation of the provided key but instead returns the key itself, or an object with the translation key and provided options. This way you can use the same function to test that the correct translation values were provided.

SQL statement matchers

manyOf

This function can be used to create multiple (exactly three) test objects.

interface MyObject {
    id: string,
    value: number,
}

// Function to create an instance of MyObject with random values
function createMyObject (template?: Partial<MyObject>): MyObject {
    return {
        id: getRandomId(),
        value: getRandomValue(),
        ...template,
    };
}

// In a test:
const myObjects = manyOf(createMyObject);

// Or setting fix values
const myObject = manyOf(() => createMyObject({ value: 42 }));

// Or setting values by index
const myObject = manyOf(createMyObject, index => ({ id: `${index}` }));