Visual Regression Testing for Mobile

Introduction

Visual regression testing is crucial for ensuring that the UI of mobile applications appears as intended after changes. It detects unintended visual changes that may occur due to code updates.

Key Concepts

• Visual Regression Testing: A method to verify UI changes using screenshots to compare pixel differences.
• Baseline Images: The original images used for comparison.
• Diff Images: Images that highlight the differences between the baseline and the current version.

Step-by-Step Process

The following steps outline the visual regression testing process for mobile applications:

flowchart TD
    A[Start] --> B{Is the app built?}
    B -- Yes --> C[Capture Baseline Images]
    B -- No --> D[Build the app]
    D --> C
    C --> E[Run Tests]
    E --> F{Are there any visual differences?}
    F -- Yes --> G[Review Differences]
    F -- No --> H[Pass Test]
    G --> I[Update Baseline if needed]
    I --> J[End]
    H --> J
        

Best Practices

• Use a dedicated visual testing tool like BackstopJS or Applitools.
• Run tests on real devices and emulators for comprehensive coverage.
• Regularly update baseline images to reflect intentional changes.
• Incorporate visual regression testing into CI/CD pipelines for continuous feedback.