MSE-SoftwEng/web-app/tests/tests.md

Test Documentation

This document describes the automated tests implemented for the Home Monitor project. The tests are written with Cypress and are organized into two distinct categories: unit tests and end-to-end (E2E) tests.

Test Types and Structure

The tests are organized in separate folders according to their type:

1. Unit Tests (tests/unit/)

Unit tests focus on testing individual components or classes in isolation, without dependencies on other parts of the system.

• Example: Serie.spec.ts - Tests the Serie class methods and functionality in isolation
• Purpose: Verify that individual components work correctly on their own
• Characteristics: Fast, focused, and test a single unit of code

2. End-to-End Tests (tests/e2e/)

E2E tests simulate real user scenarios by testing the entire application flow from start to finish.

• Example: app.spec.ts - Tests complete user workflows like navigating the application and interacting with charts
• Purpose: Verify that the entire application works as expected from a user's perspective
• Characteristics: Most comprehensive, test the entire system, slower than other test types

Configuration

Tests use a custom configuration in cypress.unit.js that allows different test types to run with appropriate settings. Key features:

• Unit tests run without isolation (can share context)
• E2E tests run with isolation (fresh environment for each test)
• All tests can run without requiring a server (baseUrl is set to null)
• Optimized settings for performance (no videos, screenshots disabled by default)

Running Tests

Running Specific Test Types

# Run unit tests
npm run test:unit

# Run E2E tests
npm run test:e2e

Running All Tests

npm run test

Using Cypress GUI

To run tests through the Cypress graphical interface:

npm run cypress:open

This method is particularly useful during development, as it allows you to:

• View tests in real-time
• Inspect DOM elements
• Replay individual tests
• See a detailed overview of the executed steps

Detailed Test Examples

Unit Tests for Serie Class

The unit tests (tests/unit/Serie.spec.ts) verify that the Serie class works correctly in isolation:

• Initialization: Tests that the class initializes with the correct properties
• Label Generation: Tests that the getLabel() method returns the correct label based on series type
• Data Formatting: Tests that the getSerie() method correctly formats data for the chart library

E2E Tests for Application

The E2E tests (tests/e2e/app.spec.ts) verify complete user workflows:

• Application Loading: Tests that the application loads correctly
• Data Display: Tests that temperature and humidity data are displayed properly
• Filtering: Tests that users can filter data by date range
• Room Selection: Tests that users can switch between different rooms
• Error Handling: Tests that errors are handled gracefully

Test Data Structure

The tests use mock data in the following format:

const mockData = [
  { time: 1625097600000, value: new Date(22.5) },
  { time: 1625184000000, value: new Date(23.8) }
];

Where:

• time: Unix timestamp in milliseconds
• value: Value encapsulated in a Date object (according to the current implementation)

Special Note on Date Usage

The Serie class uses Date objects to store temperature and humidity values, which is a unique approach. In the test code, we create Date objects by directly passing the numeric values to the constructor:

new Date(22.5)  // For a temperature of 22.5°C
new Date(45)    // For a humidity of 45%

This approach is specific to the current implementation of the Serie class and might be modified in the future to directly use numeric values.

Best Practices

Test Organization

1. Test Hierarchy:

   • Unit tests -> E2E tests
   • Tests should get progressively more comprehensive
   • Most of your tests should be unit tests (faster and more focused)

2. AAA Structure: Tests follow the Arrange-Act-Assert pattern:

   • Arrange: Prepare test data and environment
   • Act: Execute the action being tested
   • Assert: Verify the expected results

3. Isolation: Each test should be independent and not depend on shared state

Test Troubleshooting

If tests fail, check the following:

1. Server Issues: If you're running E2E tests that require a server, make sure it's started on the appropriate port

2. API Changes: If the classes or components are modified, tests must be updated accordingly

3. Synchronization Issues: Cypress might need additional time for certain operations

4. Environment Issues: Verify that all dependencies are installed with npm install

Future Test Extensions

The current tests cover basic functionality. In the future, it would be useful to add:

1. More unit tests for all components and services
2. More comprehensive E2E tests covering all user scenarios
3. Performance tests for operations on large data sets