Hey you! Why do you not writing tests? Maybe you don’t know why do you need to write them? Maybe you have doubts about who should write tests? Or your manager doesn’t give you time to write tests? Or you just don’t know how to write tests or choose the right technologies, or how to choose between UI, integration or unit test for your case? Come to my talk, and we will figure out that together!

1. No excuses for
not writing tests
Andrii
Shumada
Summer. Sea. JavaScript.

2. They take time to write
Why do you not write test?
Management asks for
features, not tests
I don’t know how to write
tests
I don’t know why I need to
write test

3. Agenda
1. What are the “tests” or “autotests”
2. Why do we need to write [auto]tests
3. Kinds of tests
4. What technologies I recommend for writing tests
5. F.A.Q.

4. What are the tests
or “autotests”

5. function validateEmail1(email) {
const re =
/^(([^<>()[].,;:s@"]+(.[^<>()[].,;:s@"
]+)*)|(".+"))@(([[0-9]{1,3}.[0-9]{1,3}.[0-9]{1
,3}.[0-9]{1,3}])|(([a-zA-Z-0-9]+.)+[a-zA-Z]{2
,}))$/;
return re.test(String(email).toLowerCase());
}
function validateEmail2(email) {
const re =
/^(([^<>()[].,;:s@"]+(.[^<>()[].,;:s@"
]+)*)|(".+"))@(([[0-9]{1,3},[0-9]{1,3}.[0-9]{1
,3}.[0-9]{1,3}])|(([a-zA-Z-0-9]+.)+[a-zA-Z]{2
,}))$/;
return re.test(String(email).toLowerCase());
}

7. function validateEmail(email) {
const re =
/^(([^<>()[].,;:s@"]+(.[^<>()[].,;:s@"]+)*)|(".+"))@(([[0-9]{1
,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}])|(([a-zA-Z-0-9]+.)+[a-zA-Z]{2,
}))$/;
return re.test(String(email).toLowerCase());
}
function testValidateEmail() {
if (validateEmail('525235235235') === false) {
console.log('Negative test 1 passed');
} else {
console.log('Negative test 1 failed');
}
if (validateEmail('eagleeyes91@gmail.com') === true) {
console.log('Positive test 1 passed');
} else {
console.log('Positive test 1 failed');
}
}
testValidateEmail();

8. Why do we need to write [auto]tests

9. UI
POST /login
http
Server

12. C
O
M
M
O
N
C
O
M
M
O
N
C
O
M
M
O
N
C
O
M
M
O
N
C
O
M
M
O
N
C
O
M
M
O
N

14. How to test it?

18. Money-driven decision maker**

19. OR
AutoTests!

20. `npm i` changes everything!

21. ➜ nest-sandbox git:(master) ✗ npm ls
nest-sandbox@0.0.1 /Users/ukr-andriishumada/prj/nest-sandbox
├─┬ @nestjs/cli@7.1.2
│ ├─┬ @angular-devkit/core@9.1.0
│ │ ├── ajv@6.12.0 deduped
│ │ ├── fast-json-stable-stringify@2.1.0 deduped
│ │ ├─┬ magic-string@0.25.7
│ │ │ └── sourcemap-codec@1.4.8
│ │ ├─┬ rxjs@6.5.4
│ │ │ └── tslib@1.11.1 deduped
│ │ └── source-map@0.7.3
│ ├─┬ @angular-devkit/schematics@9.1.0
│ │ ├── @angular-devkit/core@9.1.0 deduped
│ │ ├── ora@4.0.3 deduped
│ │ └─┬ rxjs@6.5.4
│ │ └── tslib@1.11.1 deduped

22. ➜ nest-sandbox git:(master) ✗ npm audit
found 4716 vulnerabilities (4713 low, 3 high) in 1271scanned packages

23. "dependencies": {
"@nestjs/common": "^7.0.0",
"@nestjs/core": "^7.0.0",
"@nestjs/platform-express": "^7.0.0",
"reflect-metadata": "^0.1.13",
"rimraf": "^3.0.2",
"rxjs": "^6.5.4"
},
"devDependencies": {
"@nestjs/cli": "^7.0.0",
"@nestjs/schematics": "^7.0.0",
"@nestjs/testing": "^7.0.0",
"@types/supertest": "^2.0.8",
"@typescript-eslint/eslint-plugin": "^2.23.0",
"@typescript-eslint/parser": "^2.23.0",
"eslint": "^6.8.0",
"eslint-config-prettier": "^6.10.0",
"eslint-plugin-import": "^2.20.1",
"jest": "^25.1.0",
"prettier": "^1.19.1",
"supertest": "^4.0.2",
"ts-jest": "25.2.1",
"ts-loader": "^6.2.1",
"ts-node": "^8.6.2",
"tsconfig-paths": "^3.9.0",
"typescript": "^3.7.4"
},

24. OR
AutoTests!

25. OR
AutoTests!

27. What else can change
- Node.js version!!!
- Any package version!!!
- Linux version!!
- Database version!!
- Whatever in infrastructure version!!

28. OR
AutoTests!

29. BDD
Bablo Driven
Development

30. Another good reason: TDD
(Test Driven Development)

31. Flow 1: No
tests
1. Write or adjust code
2. Restart app
[okay, maybe you have
live reload]
3. Repeat user flow
click by click
4. Check result
5. Repeat from step 1
Flow 2: TDD
1. Write tests
2. Write or adjust code
3. Restart test
4. Repeat from step 2

32. BDD
Bablo Driven
Development

33. Kinds of tests
UI Integration Unit

34. Unit testsfunction validateEmail(email) {
const re =
/^(([^<>()[].,;:s@"]+(.[^<>()[].,;:s@"]+)*)|(".+"))@(([[0-9]
{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}])|(([a-zA-Z-0-9]+.)+[a-zA-Z
]{2,}))$/;
return re.test(String(email).toLowerCase());
}
function testValidateEmail() {
console.log('Start negative test 1');
if (validateEmail('525235235235') === false) {
console.log('Negative test 1 passed');
} else {
console.log('Negative test 1 failed');
}
console.log('Start negative test 2');
if (validateEmail('eagleeyes91@gmail.com') === true) {
console.log('Positive test 1 passed');
} else {
console.log('Positive test 1 failed');
}
}
testValidateEmail();

35. Integration tests
Send HTTP
request
get response
- Check status code
- Check response code

36. const app = require('express');
const request = require('request');
app.post('/', (req, res, next) => {
res.json({message: 'success'});
});
app.listen(3533, () => {
request.post('http://localhost:3533/', {json: true},
(err, res) => {
if(err) throw err;
if(resp.statusCode === 200 && resp.body.message ===
'success') {
console.log('Integration test ok!');
} else {
console.log('Integration test failed!');
}
process.exit(0);
});
});
Not a
production-grade
code!

37. UI tests

38. Mobile
http://appium.io/

39. UI tests
Selenium based
e.g https://webdriver.io/
Puppeteer or puppeteer based frameworks

40. How Selenium works

41. When use Selenium (Webdriver.io)
- Your app has problems in different browsers (IE, Safari)
- Your manager is VERY afraid, that something will not work in particular
browser
- Without automation your QA’s are always doing regression tests in different
browsers
Pros:
- Supports all major
browsers
Cons:
- Needs Java runtime
- More complicated setup

42. How Puppeteer works
Chrome DevTools Protocol

43. When use Puppeteer
- In all other cases
- You don’t need Java
Runtime
- Faster setup
- Works faster
Pros Cons
- Supports only
Chromium and
Firefox
(experimental)

44. Test example on Puppeteer
const puppeteer = require('puppeteer');
browser = await puppeteer.launch({headless: false});
page = await browser.newPage();
const randEmail =
`testUser_${Math.random().toString().split('.')[1]}@zail.com`;
await page.goto('google.com/registration', {waitUntil: 'networkidle2'});
await page.type('form input[name="first_name]', 'Ololosha');
await page.type('form input[name="last_name] ', 'Petrovych');
await page.type('form input[name="emair] ', randEmail);
await page.type('form.reg—form form input[name="password"', '123456');
await page.click('form.reg—form form button[type="submit1');
await page.waitFor('[href="/account"');
await page.click('[href="/account"');
await page.waitFor('.personal—banner');

45. How to choose test framework?
Mocha:
- Mature
- Stable
- No assertion
framework
Jest:
- Mature
- Stable
- Bundled with CreateReactApp
Tap, Cucumber, Jasmine:
- less functional
- Less maintable
- Require more work from development

46. My choice
Mocha + Chai, because it’s stable, functional
and works
If you just starting writing tests - stick to Jest,
it’a a bit faster

47. Test structure in test frameworks
describe('feature 1', () => {
before(() => {
//test setup here
})
it('should ', () => {
//check expectations
});
});

48. Which test to write,
unit, integration, UI
UI
Integration
Unit
Better emulates
User experience
Harder to write and
maintain

49. Which test to write,
unit, integration, UI
UI
Unit
Integration
Integrations tests work as a contract between frontend and
backend, your API should be more stable than
implementation behind them

50. Tests as a part of CI CD
- Always run tests on CI
- Only CI will guarantee, that tests keep green on master
- Make a CI process that merges master into your branch, run tests and after
pushes to origin/master

51. F.A.Q.

52. Business is not giving time to write tests..
And business has right!
Just tests are not bringing value as tests!

53. Eighter show, how much money they lose without tests or just
include tests in code writing time! Tests are also code
Business understands only money!
BDD
Bablo Driven
Development

54. Who needs to write tests - AutomationQA or developer
If you have dedicated AutomationQA - then probably Automation QA with help of
developers
Otherwise - developers should write tests.

55. Useful links:
http://appium.io/
https://pptr.dev/
https://eagleeye.github.io
Highload, BigData, Node.js, AWS
Andrii Shumada
@eagleeye