Android Testing Masterclass – A Complete Blog Series

 A step-by-step guide to mastering Unit Testing, UI Testing, and End-to-End Testing in Android.


This post is the official index and will be updated as the series progresses.

Welcome

If you're an Android developer who’s ever struggled with fragile code, broken UIs, or unpredictable bugs, this series is for you.

This is a complete, no-fluff tutorial series on Android testing — from unit tests with JUnit to UI tests with Espresso, mocking with Mockito, integration strategies, and clean architecture. Each post also includes interview questions and answers to help you prepare for technical interviews or strengthen your foundations.

All content is self-contained within the blog — no external repos or tools required.

What You’ll Learn

  • Writing unit tests for business logic with JUnit

  • Mocking dependencies with Mockito

  • Creating stable UI tests using Espresso

  • Structuring integration and end-to-end tests

  • Practicing test-driven development (TDD)

  • Designing testable app architecture

  • Answering common Android testing interview questions

Blog Series Index

Each post includes:

  • Full Kotlin code examples

  • Explanations with Android Studio screenshots where needed

  • Interview questions and answers related to each topic

Introduction

Part Title Status
1 Why Testing Matters in Android Development Coming soon
2 Types of Tests: Unit, UI, Integration & E2E Coming soon

Unit Testing with JUnit & Mockito

Part Title Status
3 Setting Up Your First Unit Test in Android Studio Coming soon
4 Testing ViewModels and Business Logic Coming soon
5 Mocking with Mockito: Best Practices Coming soon
6 Parameterized Tests & Edge Case Coverage Coming soon

UI Testing with Espresso

Part Title Status
7 Getting Started with Espresso UI Tests Coming soon
8 Advanced UI Testing: Lists, Idling Resources, Navigation Coming soon
9 Organizing and Debugging UI Tests Coming soon

Integration and End-to-End Testing

Part Title Status
10 Testing Repositories with Fake Data Sources Coming soon
11 Full End-to-End Testing Workflow Coming soon

TDD, Architecture & Final Project

Part Title Status
12 Writing Features with Test-First (TDD) Approach Coming soon
13 Architecting Your App for Testability Coming soon
14 Testing Jetpack Compose UIs Coming soon
15 Final Project: A Fully Tested Mini App Coming soon

How to Use This Series

This is a hands-on series. You are encouraged to:

  • Follow along by writing the code in Android Studio

  • Use each post to understand not just the “how,” but the “why” behind testing decisions

  • Review the interview Q&A section at the end of every post for real-world technical prep

Interview Preparation Included

Each blog ends with Android interview-style questions and answers, including:

  • What’s the difference between unit, integration, and UI tests?

  • How do you test a ViewModel that uses coroutines?

  • What are idling resources in Espresso and why are they important?

  • What makes an Android app architecture testable?

This series is designed to help you grow both as a developer and a job candidate.

Stay Connected

If you find this series valuable:

  • Follow me here on Medium for future posts

  • Bookmark this index so you can revisit it anytime

  • Leave a comment with questions, feedback, or topics you’d like covered

  • Share this with other Android devs who want to improve their testing practices

Coming Up Next

Part 1: Why Testing Matters in Android Development
This post will cover the real-world cost of not writing tests, and how testing can speed up development instead of slowing it down.

To get notified when it's published, make sure to follow this blog.


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