ProvaLab Blog

13 November 2026 · 12 min read

k6 in practice: open vs closed models, per-endpoint thresholds, checks that count, and finding the limit

Hands-on: a k6 test passed at 60 users while the API managed only 46 of the 60 orders a second. Open-model scenarios, tagged thresholds, checks that fail a run, and a ramp to the limit.

13 November 2026 · 12 min read

ZAP in practice: scanning behind a login with the Automation Framework, failing the build, and what no scanner finds

Hands-on: a ZAP scan that never signed in missed the XSS behind the login. We fix that with an Automation Framework plan, triage 3 alerts that are 1 bug, fail CI on High, and test what ZAP can't.

Testing in Practice · Part 18

12 November 2026 · 10 min read

Cross-browser testing (hands-on): Chromium, Firefox and WebKit, and two bugs only Safari users would see

Run the same tests on three browser engines with Playwright. A real run in the official Docker image: a cut-off button and a broken feature only in WebKit, and an old Safari trap that's gone.

Testing in Practice · Part 16

12 November 2026 · 12 min read

Flaky tests (hands-on): measure them, reproduce them, fix the cause, and the one that was a real bug

Find and fix flaky tests with pytest. A real 100-run measurement finds four causes: shared state, timing, the clock and randomness. Retries made it worse, and one flaky test was a real bug.

Testing in Practice · Part 15

12 November 2026 · 13 min read

Localization testing (hands-on): Hindi, German and Arabic, pseudo-localization, and 16 failures on one page

Test an app in other languages with Playwright and pytest: pseudo-localization, text that doesn't fit, Indian and German number formats, ambiguous dates, Arabic plurals and right-to-left.

Testing in Practice · Part 17

12 November 2026 · 9 min read

Property-based testing with Hypothesis (hands-on): seven examples passed, three bugs found, and one property that lied

Describe what must always be true and let Hypothesis find the inputs that break it. A real run on FoodNow's money code: three bugs, shrunk to the smallest input, and two honest limits.

12 November 2026 · 14 min read

pytest in practice: fixtures, parametrize, raises, markers and the plugins worth knowing

Hands-on: a six-test pytest suite with 81% coverage caught none of three bugs. We rebuild it with parametrize, raises with match, fixtures, monkeypatch, strict markers and coverage.

Testing in Practice · Part 8

11 November 2026 · 13 min read

BDD with pytest-bdd (hands-on): Given/When/Then, and the question that wasn't a bug

Behaviour-driven development explained with FoodNow's checkout pricing. A real pytest-bdd run finds two planted bugs and a rule nobody agreed on, plus two traps.

Testing in Practice · Part 7

11 November 2026 · 15 min read

Contract testing with Pact (hands-on): the API change both teams' tests missed

Contract testing explained with Pact and pytest on a FoodNow app and its orders API. A real run: an API change passes the API team's tests, and Pact catches it, plus a lost tip.

Testing in Practice · Part 12

11 November 2026 · 13 min read

Your first Cypress test (hands-on): retrying assertions, cy.intercept, and a test that passed too early

Write a first Cypress test for a FoodNow order page. A real run finds three bugs, two of them only by faking the network with cy.intercept, and a race test that passed on the buggy page.

Testing in Practice · Part 11

11 November 2026 · 11 min read

Your first Selenium test (hands-on): Python, pytest, and the two errors every beginner hits

Write a first Selenium WebDriver test in Python with pytest. A real run hits a blocked click and a total read too early, then finds a planted bug. Plus how it compares with Playwright.

Testing in Practice · Part 6

11 November 2026 · 13 min read

Mobile app testing with Appium and pytest (hands-on): rotation, crashes and the button you can't reach

Test an Android app on an emulator with Appium and pytest. A real run finds three bugs a web test never would: a tip lost on rotation, a crash, and a Pay button off screen.

Testing in Practice · Part 5

11 November 2026 · 11 min read

Test doubles (hands-on): mocks, stubs, fakes and spies, and how a mock lets a real bug through

Dummy, stub, spy, mock and fake, explained with one payment example. A real run: MagicMock tests pass with two bugs in the code, then fail when the code is fixed.

Testing in Practice · Part 13

11 November 2026 · 12 min read

Test estimation (hands-on): three-point estimates, a 100,000-run simulation, and why adding up 'most likely' fails

How to estimate testing from the work, not a guess. Three-point estimates, a simulation and past results show why the sum of 'most likely' times is met only 9% of the time.

Testing in Practice · Part 14

11 November 2026 · 13 min read

The test summary report (hands-on): 96.8% passed, not ready to release, and the metrics that tell you why

How to write a test summary report people can decide from. A real report built from five suites' results: a 96.8% pass rate, two high-risk gaps, and a test that fails every night.

Testing in Practice · Part 4

11 November 2026 · 14 min read

Testing database changes (hands-on): transactions, race conditions and migrations with SQL and pytest

What to check when code writes to a database. A real PostgreSQL run: a refused order that still saves, 20 customers buying 10 wraps, and a migration that fails on real data.

Testing in Practice · Part 10

11 November 2026 · 13 min read

Usability testing (hands-on): a heuristic review, five users, and the form that threw away a correct address

How to find what makes users give up: a heuristic review of a real form, measured tap targets, why five users is enough (and when it isn't), and SUS scoring.

Testing in Practice · Part 9

11 November 2026 · 14 min read

User acceptance testing (hands-on): plan, dry run and sign-off, and the bug only the UAT server had

How to plan and run UAT so it isn't a rubber stamp. A real dry run on a UAT-like server finds a time-zone bug that passed every system test; a script checks the exit criteria.

Testing in Practice · Part 1

10 November 2026 · 13 min read

Accessibility testing for beginners: WCAG 2.2, an axe scan and keyboard tests (hands-on)

What accessibility testing checks, what WCAG 2.2 A and AA mean, then a real run: axe-core, a keyboard test and a screen-reader names test catch planted bugs on a checkout page.

Testing in Practice · Part 2

10 November 2026 · 12 min read

API testing with Postman and Newman (hands-on): tests, variables, a CSV of boundary values, and CI

Build a Postman collection with tests and chained variables, run it from the command line with Newman, then drive it from a CSV of boundary values that catches a real bug.

Testing in Practice · Part 3

10 November 2026 · 10 min read

Visual regression testing with Playwright (hands-on): screenshots, baselines, masks and thresholds

Catch the layout bugs functional tests can't see. A real run: a one-line CSS change breaks a checkout page, every functional test passes, and a Playwright screenshot test catches it.

Hands-On Testing · Part 7

30 October 2026 · 8 min read

Your first load test with k6 (hands-on): find where your API slows down

Write and run a k6 load test against the API from Part 4, set pass/fail thresholds, read the summary, then run a stress test to 1,000 users and find where it slows, with the real output.

30 October 2026 · 10 min read

Playwright with Python in practice: fixtures, page objects, saved state, mocked APIs and parallel runs

Hands-on: grow three Playwright tests into a real suite with page objects, pytest fixtures, saved browser state, an API mocked with page.route, and a parallel run that more than halves the time.

30 October 2026 · 10 min read

50 software testing interview questions, with short answers and where to read more

The questions QA and test automation interviews actually ask, grouped by topic, each with a two-sentence answer and a link to the full explanation in our Testing Basics and Hands-On series.

Hands-On Testing · Part 3

29 October 2026 · 7 min read

API testing explained: what it is, why test the API before the UI, and what to check

What an API is and how API tests work, why they are faster and more stable than UI tests, the five things to check in every response, the kinds of API tests, and the tools teams use.

Testing Basics · Part 7

29 October 2026 · 6 min read

Test design techniques: black-box, white-box and grey-box testing

The three ways of looking at software when you design tests, and the techniques for each, from boundary values and state transitions to statement and branch coverage.

Testing Basics · Part 10

29 October 2026 · 5 min read

The bug life cycle explained: from New to Closed (and Reopened)

Every status a bug passes through, who moves it at each step, the side exits like Duplicate and Deferred, one bug followed from start to finish, and the habits that keep a bug tracker healthy.

Testing Basics · Part 22

29 October 2026 · 6 min read

Exploratory testing explained: charters, sessions and heuristics

What exploratory testing is and isn't, how session-based testing works, how to write a charter, the heuristics skilled testers use to generate ideas, and how to report what you found.

Hands-On Testing · Part 4

29 October 2026 · 8 min read

Your first API tests in 15 minutes (Python, pytest and requests)

Build a tiny discount API you own, then write eleven pytest tests against it: functional, contract, negative, authentication and authorisation checks, with the real output and a planted bug.

Testing Basics · Part 5

29 October 2026 · 5 min read

Your first automated test in 15 minutes (Python + pytest)

A hands-on, step-by-step guide to writing and running your first automated tests with Python and pytest, including what a failing test looks like and how to read it.

Hands-On Testing · Part 2

29 October 2026 · 7 min read

Your first Playwright test in 15 minutes (Python)

Install Playwright for Python, write three browser tests against a real website, run them headless, break one on purpose and read the failure, record a trace, and run the suite in CI.

Hands-On Testing · Part 6

29 October 2026 · 9 min read

Your first security scan with OWASP ZAP (hands-on)

Run a real DAST scan with OWASP ZAP against the API from Part 4, read the report, plant a SQL injection and watch the scanner find it, triage the findings, fix the bug and re-scan.

29 October 2026 · 3 min read

How do you test code your AI coding agent wrote?

AI agents write features in minutes, but most teams still check that code the old way. Here is a practical way to verify AI-written code before it ships.

Testing Basics · Part 9

29 October 2026 · 5 min read

How to write a good bug report (with template and examples)

What makes a bug report easy to act on, every field to include, severity vs priority explained, a good and a bad example side by side, and a copy-ready template.

Testing Basics · Part 8

29 October 2026 · 5 min read

How to write a test plan (with a one-page example)

What a test plan is, the sections every plan needs, a one-page example you can copy, risk-based testing, and how test plans work in agile teams.

Testing Basics · Part 6

29 October 2026 · 5 min read

How to write good test cases: template, examples and techniques

What goes into a test case, a ready-to-use template with real examples, the techniques testers use to pick the right cases, and the mistakes to avoid.

Testing Basics · Part 12

29 October 2026 · 6 min read

Integration testing explained: approaches, stubs, drivers and examples

What integration testing is, why bugs hide where components meet, the big bang, top-down, bottom-up and sandwich approaches, stubs and drivers, and what to check at every integration point.

Testing Basics · Part 3

29 October 2026 · 5 min read

Manual vs automated testing: what to automate, and what not to

When a person should test and when a machine should, how to decide what to automate, what automation really costs, and the tools teams use.

29 October 2026 · 7 min read

MCP, plugins and skills, explained: how AI agents use ProvaLab

What MCP is, how Claude Code plugins and skills fit around it, what changed in the new stateless MCP, and how your coding agent can use ProvaLab through it.

Testing Basics · Part 16

29 October 2026 · 7 min read

Performance testing and its types: load, stress, spike, soak, volume and scalability

What performance testing is, the six main types and when to use each, the metrics that matter (and why averages lie), how to run a performance test step by step, and the common mistakes.

Testing Basics · Part 20

29 October 2026 · 6 min read

QA vs QC vs testing, and verification vs validation, explained

The difference between quality assurance, quality control and testing, and between verification and validation, with simple definitions, examples, the V-model, and comparison tables.

Testing Basics · Part 15

29 October 2026 · 6 min read

Regression testing vs re-testing: what they are and why we do both

Why every bug fix needs re-testing, how regression testing catches what a change broke elsewhere, the differences between them, how to choose regression tests, and how to keep a regression suite fast.

Testing Basics · Part 11

29 October 2026 · 6 min read

The requirements traceability matrix (RTM): prove everything is tested

What a traceability matrix is, how to build one step by step, forward and backward traceability, how to measure coverage, and how it answers "are we ready to release?"

Hands-On Testing · Part 5

29 October 2026 · 8 min read

Security testing basics: the OWASP Top 10 (2025) in plain language

What security testing is, the ten risks in the OWASP Top 10 2025 explained with everyday examples, the six kinds of security testing and which tools do them, and the checks you can add this week.

Testing Basics · Part 19

29 October 2026 · 6 min read

The 7 principles of software testing, explained with examples

The seven testing principles from the ISTQB syllabus in plain language, each with a real-world example and what it means for how you test day to day.

Testing Basics · Part 14

29 October 2026 · 5 min read

Smoke testing vs sanity testing: the difference, with examples

What smoke testing and sanity testing are, how they differ, when to use each, example checklists for a real app, and how to automate them.

Testing Basics · Part 4

29 October 2026 · 6 min read

The Software Testing Life Cycle (STLC): all six phases explained

The six phases of the STLC in plain language, with what goes in and comes out of each, entry and exit criteria, how STLC fits the SDLC, and how it works in agile teams.

Testing Basics · Part 21

29 October 2026 · 7 min read

Static testing explained: reviews, walkthroughs, inspections and static analysis

How to find defects without running the software: the four types of review, the review process, static analysis tools with a real example, and why static testing is the cheapest testing there is.

Testing Basics · Part 13

29 October 2026 · 6 min read

System testing explained: testing the whole product, end to end

What system testing is, how it differs from integration and acceptance testing, its functional and non-functional types, example test cases, and how to do it well.

Testing Basics · Part 18

29 October 2026 · 7 min read

Test coverage explained: the types, and how to calculate each one

The main kinds of test coverage (requirement, execution, code and platform), the formula for each with worked examples, sensible targets, and why 100% coverage isn't bug-free.

Testing Basics · Part 17

29 October 2026 · 6 min read

Test runs and test results explained: statuses, pass rates and how to read them

What a test run and a test result are, how they relate to test cases, every result status, how to calculate pass rates correctly, and how to read a run so nothing important is missed.

Testing Basics · Part 23

29 October 2026 · 8 min read

Testing in agile and CI/CD: how it all fits together

How testing works when a team ships every week or every day: whole-team quality, the agile testing quadrants, shift-left and shift-right, TDD and BDD, and testing at every stage of a CI/CD pipeline.

Testing Basics · Part 2

29 October 2026 · 5 min read

Types of software testing explained: unit, integration, system and acceptance

The four levels of software testing in plain language, with one running example, plus the testing pyramid and the other testing words you will hear at work.

Hands-On Testing · Part 1

29 October 2026 · 8 min read

UI testing explained: what it is, how it works, and Selenium vs Playwright vs Cypress

What UI testing is and what it's for, how a browser test actually works, how to choose locators that don't break, why UI tests go flaky, and an honest comparison of Selenium, Playwright and Cypress.

Testing Basics · Part 1

29 October 2026 · 5 min read

What is software testing, and why does every team need it?

A plain-language introduction to software testing: what it is, what it checks, when it happens, who does it, and the myths that trip teams up.