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Testing Your Lens

Testing Philosophy

Comprehensive testing ensures your Lens operates correctly, maintains regulatory compliance, and delivers the intended personalization without removing regulated content. Use a combination of automated unit tests and visual inspection to validate your lens implementation.

Testing lenses involves two complementary approaches: automated unit testing for functionality validation and visual testing for user experience verification.

Unit Testing​

Overview​

The lens-template repository includes a comprehensive test suite that enables automated testing of your lens implementation. Unit tests validate that your lens:

  • Does not remove or alter regulated content
  • Applies correct CSS classes (highlight, collapse) based on patient data
  • Adds supplementary content in appropriate locations
  • Handles edge cases and invalid inputs gracefully
  • Performs within acceptable execution time limits
Critical Compliance Test

The most important test validates that no content is removed from the original ePI. This ensures regulatory compliance and patient safety.

Read the Test README for more detailed information about testing and developing tests.

Running Unit Tests​

The lens template provides npm scripts for running tests:

# Run all tests once
npm test

# Run tests in watch mode (re-runs on file changes)
npm test -- --watch

# Run tests with coverage report
npm test -- --coverage

# Run specific test file
npm test -- path/to/test-file.test.js

Test Structure​

A typical lens test suite includes:

  1. Content Preservation Tests
  2. Functional Tests, These verify your lens applies the correct focusing logic.
  3. Edge Case Tests, Test boundary conditions and error handling.
  4. Supplementary Content Tests

Test Data Customization​

The lens template includes sample test data that you should customize for your use case.

Best Practices for Unit Testing​

Testing Best Practices
  1. Test one thing at a time: Each test should validate a single behavior
  2. Use descriptive test names: Clearly state what is being tested
  3. Test both positive and negative cases: Verify expected behavior and error handling
  4. Keep tests independent: Tests should not depend on each other's state
  5. Use test fixtures: Create reusable test data to avoid duplication
  6. Aim for high coverage: Target 80%+ code coverage for critical lens logic
  7. Run tests frequently: Test after each significant code change

Visual Testing​

Using the Focusing Inspector​

The Focusing Inspector tool provides a visual interface for testing lens operation and seeing the actual rendered output. This tool is part of the focusing-SDK and enables you to:

  • Preview how your lens transforms ePI content
  • Inspect applied CSS classes visually
  • Verify supplementary content appears correctly
  • Test with different IPS and ePI combinations
  • Debug focusing logic in real-time
Tool Location

The Focusing Inspector is available in the focusing-SDK repository. See the Focusing Inspector reference for detailed information.

Setting Up Visual Testing​

1. Install the Focusing SDK​

# Clone the focusing-SDK repository
git clone https://github.com/Gravitate-Health/focusing-sdk.git
cd focusing-sdk

# Start the Focusing Inspector
docker-compose up -d

2. Load Your Lens​

There are 3 main methods to load your lens into the SDK

  1. The easiest is just to copy/develop your lens in the Lenses folder. There is a lens-selector-file already configured to monitor this folder.
  2. You can add another lens-selector-file service which monitors another folder in your file system.
  3. add a lens-selector-git service pointing to your git repository (remember to set CACHE_TTL_MINUTES to 0 if you want it to load the latest commit every time)

3. Execute and Inspect​

Once loaded:

  • Execute prerequisites, which are selecting an input ePI, and preprocessing it.
  • Select an IPS which will determine the patient profile (remember you can edit this in the patientfolder)
  • Execute the lens to generate the f(ePI)
  • View side-by-side comparison of original and focused ePI
  • Inspect HTML changes to see applied classes and added content
  • Toggle views between different focusing modes (programmer view vs. end-user view)

Visual Testing Checklist​

Use this checklist when visually testing your lens:

Content Verification​

  • All original text is visible or accessible (not deleted)
  • Collapsed sections can be expanded to view hidden content
  • No broken HTML structure or rendering issues

Highlighting/Collapsing​

  • Relevant sections are visually highlighted appropriately
  • Irrelevant sections are collapsed/dimmed but not removed
  • Standard sections remain with normal styling
  • Visual hierarchy makes sense for patient understanding

Supplementary Content​

  • Added links open to correct destinations
  • Added images/icons display correctly
  • Added interactive elements function properly
  • New content doesn't obscure original information

Patient Context Scenarios​

  • Test with different ages (pediatric, adult, geriatric)
  • Test with various medical conditions
  • Test with different medication lists
  • Test with edge cases (missing data, extreme values)

Performance​

  • Lens executes quickly (< 2 seconds for typical ePI)
  • Page remains responsive after focusing
  • No console errors or warnings

Accessibility​

  • Focus indicators work correctly for keyboard navigation
  • Color contrast meets accessibility standards
  • Screen reader compatibility (if applicable)