56 posts tagged &quot;r&quot;

24 min read

Test Doubles Taxonomy for R: Dummy, Stub, Spy, Mock, Fake

You probably call them all "mock". What each type of test double actually is, when to reach for it in R, and what goes wrong when you mix them up.

Jun 12, 2026

14 min read

11 Test Smells That Make Your Tests Lie to You

Learn to recognize problems in R test code that cause your test suite to pass while hiding real bugs. Detect those issues and start writing more trustworthy tests.

Jun 2, 2026

22 min read

Behavior-Driven Development in R Shiny: Asserting Outcomes with Then Steps

Learn how to write Then steps that assert outcomes without coupling to implementation. Build custom testthat expectations and keep your BDD assertions at the right level.

May 29, 2026

7 min read

Behavior-Driven Development in R Shiny: Modeling User Behavior with When Steps

Learn how to write When steps that describe user actions without leaking implementation details. Build a clean DSL that survives UI refactors and keeps specifications readable.

May 26, 2026

11 min read

muttest 0.2.0: More Mutators, Better Reporting, and Parallel Execution

Expanded mutator library, improved reporting, and parallel execution for mutation testing in R.

May 15, 2026

mutation testingrtests

8 min read

Behavior-Driven Development in R Shiny: Setting Up Test Preconditions with Given Steps

Learn how to set up test preconditions in Shiny BDD using Given steps. Master dependency injection, test doubles, and composable setup patterns for reliable R testing.

Nov 3, 2025

10 min read

Simplifying Interactions with Complex Widgets in shinytest2 Using JavaScript APIs

When shinytest2's `set_inputs()` won't work, leverage widget APIs directly. Learn to write cleaner, faster and more robust tests using JavaScript APIs.

Oct 31, 2025

rshinyshinytest2tests

Behavior-Driven Development in R Shiny: A Step-By-Step Example

Follow each step as I develop a form with Shiny and Behavior-Driven Development. Learn practical techniques for better software design through automated tests.

Oct 10, 2025

13 min read

Deploy Multiple Shiny Apps from One R Package

Code organization and deployment strategy for multiple Shiny apps sharing common logic within a single R package. Structuring your project in a monorepo format.

Oct 8, 2025

deploymentrshiny

The Cadence of Behavior-Driven Development

Learn how to effectively implement Behavior-Driven Development (BDD) practices in your projects. Focus on delivering the most valuable scenarios first and avoid the pitfalls of over-specification.

Sep 30, 2025

bddrtests

Clean R Tests with `local_mocked_bindings` and Dependency Wrapping

Learn how to write reliable R tests by wrapping external dependencies and using `testthat::local_mocked_bindings`. Make your tests fast, clean, and predictable.

Sep 23, 2025

R6 Interfaces For Backend: Define What, Not How

A Practical Guide to Faking External Dependencies and Business Logic with R6 Classes for Reliable Tests.

Sep 10, 2025

How to Write Robust shinytest2 Tests for R Shiny Apps

A step-by-step guide to stronger R Shiny testing with stable selectors and reusable actions.

Aug 18, 2025

rshinyshinytest2tests

How to Test R Code That Uses LLMs, APIs, or Databases

A Practical Guide to Faking External Dependencies in R for Fast, Reliable Tests.

Aug 1, 2025

llmrtests

bddcucumberllmrshinytests

How to Write Cucumber Specifications the Right Way: From App Description to Scenarios

Adding Cucumber specifications to an existing application? Learn how to write Gherkin scenarios that focus on user behavior, not implementation details. Use AI to iterate faster.

Jul 30, 2025

Refactoring Cucumber and Playwright Acceptance Tests with GitHub Copilot

Given a set of existing Cucumber and Playwright acceptance tests, I asked Copilot to refactor them according to best practices for step organization and anti-patterns.

Jul 29, 2025

bddcucumberllmrtests

3 Reasons Blocking You From Doing Automated Testing

Get them out of your way to start testing your code effectively.

Jul 23, 2025

Testing your Plumber APIs from R

Learn how to effectively test your Plumber APIs in R using a two-layer testing strategy that separates business logic from API contracts.

Jul 20, 2025

plumberrtests

Testing Legacy Shiny Apps: Start with Behavior, Not Code

Adding acceptance tests first makes refactoring safer.

Jul 16, 2025

The 4 Layers of Testing Every R Package Needs

Discover the essential layers of testing for robust R packages: unit tests, acceptance tests, code coverage, and mutation testing.

Jul 9, 2025

An Introduction to Behavior-Driven Development in R

Learn how to use Behavior-Driven Development (BDD) in R to ensure your software meets user requirements through executable specifications.

Jul 4, 2025

bddcucumberrtests

8 min read

Keys To Scalable Code: Owning The Interfaces You Use

Learn how to build scalable and maintainable code by abstraction and information hiding, improving flexibility and ease of future changes.

Jan 23, 2025

rshiny

Acceptance Test-Driven Development with Shiny

Learn how to apply Acceptance Test-Driven Development (ATDD) to build robust Shiny applications using {shinytest2} and {selenider}.

Jan 22, 2025

Maximizing Efficiency with AI-Assisted Testing: Lessons Learned

Discover the benefits and challenges of AI-assisted testing, and learn how to optimize your testing process for better code quality and maintainability.

Jan 13, 2025

Efficient Snapshot Testing in R with CI and GitHub API

Learn how to manage snapshot tests in R using CI and GitHub API to ensure consistency across different environments.

Dec 13, 2024

How to Get Code Coverage Reports Without Sharing Code with Codecov.io

Learn how to generate code coverage reports in R using cobertura-action without sharing your private code with codecov.io.

Dec 11, 2024

Choosing the Best Library for Acceptance Testing Shiny Apps: {shinytest2} vs Cypress

Compare {shinytest2} and Cypress for acceptance testing Shiny apps. Learn their pros, cons, and which might suit your project better.

Dec 2, 2024

Optimize Your Unit Test Structure for Faster Feedback

Learn how to speed up your unit tests by optimizing the structure of your test files using testthat in R.

Nov 8, 2024

How Tests Improve Code Quality: 3 Key Insights

Discover how tests can reveal code modularity, coupling, and separation of concerns to improve your code quality.

Oct 24, 2024

Top 3 Testing Lessons from 3 Years as an R Developer

Discover the top three lessons learned from three years of testing as an R developer. Improve your testing practices with these insights.

Oct 20, 2024

Improve Your Unit Test Titles for Better Code Understanding

Learn how to write descriptive unit test titles that enhance code readability and maintainability.

Oct 13, 2024

How to Easily Capture and Test Code Output in R

Learn methods to capture and test code output in R, including snapshot testing, dput, and constructive package.

Sep 14, 2024

Optimize Shinytest2: Speed Up Your Shiny App Tests

Learn how to speed up Shiny app tests using shinytest2 by reusing application instances and refreshing the browser.

May 29, 2024

rshinyshinytest2tddtests

8 min read

Effective Testing of Shiny Components with shinytest2

Learn how to test Shiny components for correct markup and server communication using shinytest2.

May 23, 2024

Effective State Management in Shiny Modules: A React-Inspired Approach

Learn how to manage state in Shiny modules using a React-inspired approach with event handlers for better control and flexibility.

Mar 29, 2024

rshiny

Creating Robust E2E Test Selectors for Shiny Apps

Learn how to create resilient E2E test selectors in Shiny apps using data-* attributes and best practices.

Mar 15, 2024

rshinytestsui

How to Snapshot Test Excel Workbooks in Shiny Apps

Learn how to export data to Excel in Shiny apps and use snapshot tests to validate and inspect the exported workbooks.

Mar 6, 2024

Developing Shiny Modules with Test-Driven Development

Learn how to use tests to develop Shiny modules efficiently, ensuring faster development cycles and better modularization.

Mar 3, 2024

How to Set Up Cucumber for End-to-End Testing in Rhino Projects

Learn how to set up Cucumber with Cypress in Rhino projects for clear and maintainable end-to-end tests.

Feb 28, 2024

BDD Style Testing for Shiny Module Servers with R6 and testServer

Learn how to write BDD style tests for Shiny module servers using R6 and testServer to improve readability and maintainability.

Jan 30, 2024

Real-Time Input Validation Using Bootstrap Form Validation API

Learn how to implement real-time input validation in Shiny apps using Bootstrap Form Validation API for immediate feedback.

Jan 29, 2024

rshinyui

How to Use Acceptance Test-Driven Development for Shiny Modules

Learn how to apply acceptance test-driven development (ATDD) to build robust Shiny modules with R6 and shinytest2.

Dec 12, 2023

Comprehensive Guide to Testing Shiny Modules with shiny::testServer

Learn how to effectively test Shiny modules using shiny::testServer with examples and best practices.

Oct 31, 2023

3-Step Guide to Building Plots Faster with Test Driven Development

Discover how to use TDD and approval testing to rapidly develop and test plots in R.

Oct 29, 2023

rtddtestsui

How Test-Driven Development (TDD) Speeds Up Prototyping

Learn how TDD helps you prototype faster by allowing you to experiment with your code and find better solutions quickly.

Oct 29, 2023

Extending Shiny Modules with TDD in Legacy Code

Learn how to extend Shiny modules in legacy code using the Sprout Technique and Test Driven Development.

Oct 28, 2023

1 min read

How to Develop Quickly Using a New Library Without Reading Extensive Documentation

Learn how to use AI tools to use new libraries quickly without spending hours on documentation.

Oct 18, 2023

llmrtests

How to Test Code with External Dependencies Using Stubs in R

Learn how to test R functions with external dependencies using stubs and the testthat package.

Oct 17, 2023

Mastering Test-Driven Development: 3 Essential Steps for Better Code

Learn the 3 essential steps of Test-Driven Development (TDD) to improve code quality and development speed.

Mastering Test Driven Development: Build the Right Thing First

Learn how Test Driven Development (TDD) ensures you build the right thing on the first try with no rewrites.

Effective Strategies to Avoid Frustration with Legacy Code

Learn how to manage legacy code efficiently using the Sprout Technique to reduce frustration and improve productivity.

Improve Your Unit Tests with Arrange, Act, Assert Method

Learn how to write cleaner and more effective unit tests using the Arrange, Act, Assert method. Step-by-step guide with examples.

How We Achieved 96% Code Coverage in a 2-Week App Prototype

Learn how we built an app prototype with 96% code coverage in just 2 weeks using TDD and effective testing strategies.

Oct 6, 2023

3 Essential Types of Unit Tests Every R Developer Should Know

Learn about Direct Response, State Change, and Interaction Tests to improve your unit testing strategy.

Sep 25, 2023