Recently I've moved a project from plain old JavaScript to TypeScript. Previously every test was running fine. Right after the change some test cases just broke and I can not understand why. I'm using Vue.js alongside vue-test-utils and jest.
jest.config.js
module.exports = {
collectCoverageFrom: [
'/src/**/*.{js,jsx,vue}',
'!**/node_modules/**',
'!**/vendor/**',
],
moduleFileExtensions: [
'ts',
'js',
'json',
'vue',
],
transform: {
'.*\\.(vue)$': 'vue-jest',
'^.+\\.js$': 'babel-jest',
'^.+\\.ts$': 'ts-jest',
},
transformIgnorePatterns: [
'<rootDir>/node_modules/(?!vuex-class-modules).+\\.js$',
],
moduleNameMapper: {
'^@/(.*)$': '<rootDir>/src/$1',
},
setupFilesAfterEnv: [
'@testing-library/jest-dom/extend-expect',
],
};
A snippet of an example test that's failing right now, which has been working fine previously.
some.test.js
function mountStore(loggedInState) {
const store = new Vuex.Store({
modules: {
customer: {
namespaced: true,
state: {
isLoggedIn: loggedInState,
},
actions,
},
},
});
return shallowMount(Component, {
localVue,
store,
router,
stubs: { 'router-link': RouterLinkStub },
});
}
describe('Test with customer logged in at beginning', () => {
let wrapper;
beforeEach(() => {
wrapper = mountStore(true);
});
it('should redirect to home if user is logged in on init', () => {
expect(wrapper.vm.$route.name).toBe('Home');
});
});
Regarding this specific test case, the result is as following.
expect(received).toBe(expected) // Object.is equality
Expected: "Home"
Received: null
I also noticed upgrading all dependencies (including some Jest dependencies) leads to even more failing tests. So I expect that to (probably) be the reason, since I just added TypeScript support later on. However, I don't know what dependency bination would lead to a faulty behavior.
Relevant dependencies I've updated, which eventually would lead to even more failing tests.
- jest
- ts-jest
- babel-jest
Recently I've moved a project from plain old JavaScript to TypeScript. Previously every test was running fine. Right after the change some test cases just broke and I can not understand why. I'm using Vue.js alongside vue-test-utils and jest.
jest.config.js
module.exports = {
collectCoverageFrom: [
'/src/**/*.{js,jsx,vue}',
'!**/node_modules/**',
'!**/vendor/**',
],
moduleFileExtensions: [
'ts',
'js',
'json',
'vue',
],
transform: {
'.*\\.(vue)$': 'vue-jest',
'^.+\\.js$': 'babel-jest',
'^.+\\.ts$': 'ts-jest',
},
transformIgnorePatterns: [
'<rootDir>/node_modules/(?!vuex-class-modules).+\\.js$',
],
moduleNameMapper: {
'^@/(.*)$': '<rootDir>/src/$1',
},
setupFilesAfterEnv: [
'@testing-library/jest-dom/extend-expect',
],
};
A snippet of an example test that's failing right now, which has been working fine previously.
some.test.js
function mountStore(loggedInState) {
const store = new Vuex.Store({
modules: {
customer: {
namespaced: true,
state: {
isLoggedIn: loggedInState,
},
actions,
},
},
});
return shallowMount(Component, {
localVue,
store,
router,
stubs: { 'router-link': RouterLinkStub },
});
}
describe('Test with customer logged in at beginning', () => {
let wrapper;
beforeEach(() => {
wrapper = mountStore(true);
});
it('should redirect to home if user is logged in on init', () => {
expect(wrapper.vm.$route.name).toBe('Home');
});
});
Regarding this specific test case, the result is as following.
expect(received).toBe(expected) // Object.is equality
Expected: "Home"
Received: null
I also noticed upgrading all dependencies (including some Jest dependencies) leads to even more failing tests. So I expect that to (probably) be the reason, since I just added TypeScript support later on. However, I don't know what dependency bination would lead to a faulty behavior.
Relevant dependencies I've updated, which eventually would lead to even more failing tests.
- jest
- ts-jest
- babel-jest
- Since there are no piler errors, I don't think that TS itself has to be blamed. Better focus on changes that were made when you "moved a project from plain old JavaScript to TypeScript". "So I expect that to (probably) be the reason, since I just added TypeScript support later on" - then that's it, downgrade them first. – Estus Flask Commented Jan 24, 2020 at 9:26
- @Aer, I am facing the same issue. Did you e across any solution for this issue? – Amit Commented Aug 6, 2022 at 10:23
3 Answers
Reset to default 3Add
preset: 'ts-jest/presets/js-with-babel',
to jest.config.js since you use ts-jest with babel-jest. Source.
I was having a similar issue. @winwiz1's answer worked for me, but I needed to put it inside the project definition as I'm using the projects syntax. I would just leave this as a ment on @winwiz1's answer, but StackOverflow mangles the format.
projects: [
{
"displayName": "test-unit",
"preset": "ts-jest",
"testMatch": ["<rootDir>/test-unit/**/*\\.tests\\.[t|j]s"]
}
],
Did you try adding @types/jest? And adding it in your tsconfig.json:
"types": ["@types/node", "@nuxt/types", "@types/jest", "nuxt-i18n"]