Test Frameworks & Tools

The Framework Landscape

Test frameworks fall into two broad categories: unit/backend frameworks (test code logic) and UI/browser frameworks (test what users see). Most real projects use one from each category.

Framework Comparison

Playwright

Playwright (by Microsoft) is the modern standard for browser testing. It's fast, reliable, and supports Chrome, Firefox, and Safari from a single API. Built-in auto-wait eliminates most flakiness issues.

# Install: pip install playwright && playwright install
from playwright.sync_api import sync_playwright

def test_search_feature():
    with sync_playwright() as p:
        browser = p.chromium.launch()
        page = browser.new_page()
        page.goto("https://example.com")
        page.fill("#search", "QA automation")
        page.click("button.search-btn")
        assert page.locator(".results").count() > 0
        browser.close()

Key strengths:

• Auto-wait — Automatically waits for elements to be ready before interacting
• Multi-browser — Chrome, Firefox, WebKit (Safari) from one API
• Codegen — Record browser actions and generate test code automatically
• Trace viewer — Visual debugger with screenshots, network logs, and DOM snapshots
• API testing — Built-in support for HTTP requests alongside browser tests

Cypress

Cypress is a JavaScript-first testing framework that runs inside the browser. It's popular with frontend teams because tests look like the app code they already write.

// Install: npm install cypress --save-dev
describe('Login Flow', () => {
  it('should login with valid credentials', () => {
    cy.visit('/login')
    cy.get('#email').type('[email protected]')
    cy.get('#password').type('secret123')
    cy.get('button[type="submit"]').click()
    cy.url().should('include', '/dashboard')
    cy.get('.welcome').should('contain', 'Welcome, Alice')
  })
})

Key strengths:

• Time travel — Snapshots at each step; hover to see what the app looked like
• Auto-reload — Tests re-run automatically when you save files
• Network stubbing — Intercept and mock API responses easily

Selenium

Selenium is the original browser automation framework (since 2004). It supports the most languages and has the largest ecosystem, but requires more setup and explicit waits than modern alternatives.

# Install: pip install selenium
from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

driver = webdriver.Chrome()
driver.get("https://example.com/login")

# Explicit wait — Selenium doesn't auto-wait like Playwright
email = WebDriverWait(driver, 10).until(
    EC.presence_of_element_located((By.ID, "email"))
)
email.send_keys("[email protected]")
driver.find_element(By.ID, "password").send_keys("secret123")
driver.find_element(By.CSS_SELECTOR, "button[type='submit']").click()

assert "/dashboard" in driver.current_url
driver.quit()

pytest

pytest is Python's de facto testing framework. It's not just for unit tests — with plugins, it handles everything from API testing to database integration tests to Playwright browser tests.

# Install: pip install pytest
# Run: pytest tests/ -v

# Simple test — no classes needed
def test_addition():
    assert 1 + 1 == 2

# Fixtures for setup/teardown
import pytest

@pytest.fixture
def api_client():
    client = TestClient(app)
    yield client

def test_get_users(api_client):
    response = api_client.get("/api/users")
    assert response.status_code == 200
    assert len(response.json()) > 0

# Parametrized tests — run same test with different inputs
@pytest.mark.parametrize("input,expected", [
    (2, 4), (3, 9), (4, 16), (-1, 1)
])
def test_square(input, expected):
    assert input ** 2 == expected

Essential plugins:

JUnit 5

JUnit 5 is the standard testing framework for Java and Kotlin. It integrates tightly with Maven, Gradle, and Spring Boot.

import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.ValueSource;
import static org.junit.jupiter.api.Assertions.*;

class CalculatorTest {

    @Test
    @DisplayName("Addition should return correct sum")
    void testAddition() {
        Calculator calc = new Calculator();
        assertEquals(4, calc.add(2, 2));
    }

    @ParameterizedTest
    @ValueSource(ints = {1, 2, 3, 5, 8})
    void testIsPositive(int number) {
        assertTrue(number > 0);
    }
}

How to Choose

Interview Questions