vitest - generic test structures and examples

test-templates.js

import { beforeAll, beforeEach, describe, expect, it, vi } from 'vitest';

// ---------------------------------------------------------

// template unit test functions

// ---------------------------------------------------------

const isFn = (a) => typeof a === 'function';
const isString = (a) => typeof a === 'string';
const isNumber = (a) => typeof a === 'number';

// ---------------------------------------------------------

const DataObject = {
  foo: 'bar',
  baz: 'qux',
};

class SomeClass {
  constructor() {
    this.foo = 'bar';
  }

  baz() {
    return 'qux';
  }
}

function exposedFunction() {
  return {};
}

const exposedObject = {
  foo: 'bar',
  baz() {
    return 'qux';
  },
};

// ---------------------------------------------------------

it('should expose an object', () => {
  expect(exposedObject).toBeDefined();
  expect(exposedObject).toBeInstanceOf(Object);
});

it('should expose a function', () => {
  expect(exposedFunction).toBeDefined();
  expect(exposedFunction).toBeInstanceOf(Function);
});

it('should return an object', () => {
  const instance = exposedFunction();

  expect(instance).toBeDefined();
  expect(instance).toBeInstanceOf(Object);
});

it('has the expected properties', () => {
  expect(exposedObject).toHaveProperty('foo');

  expect(exposedObject.foo).toBe('bar');
});

it('should have a method baz()', () => {
  // exposedObject.baz();
  expect(exposedObject.baz).toBeDefined();
});

// ---------------------------------------------------------

let instance;

beforeAll(() => {
  instance = new SomeClass();
});

// beforeEach(() => {
//   instance = new SomeClass();
// });

it('can be instantiated', () => {
  expect(instance).toBeDefined();
  expect(instance).toBeInstanceOf(Object);
});

it('should be an instanceof SomeClass', () => {
  expect(instance).toBeInstanceOf(SomeClass);
});

it('extends from SomeClass', () => {
  expect(instance).toBeInstanceOf(SomeClass);
});

it('should have a method baz()', () => {
  // instance.baz();
  expect(instance.baz).toBeDefined();
});

// ---------------------------------------------------------

it('loads the test object correctly', () => {
  expect(DataObject).toMatchSnapshot();
});