Practical Debugging and Testing of HarmonyOS Next

Practical Guide to Debugging and Testing in HarmonyOS Next

I. DevEco Studio 5.0 Debugging Toolbox Revolution

1. Real-Time Monitoring of Memory/CPU/GPU

DevEco Studio 5.0 introduces a powerful real-time monitoring tool that allows developers to track the performance metrics of their applications. This feature is particularly useful for identifying performance bottlenecks and optimizing resource usage.

diagnoser.startMonitoring({
  metrics: ['memory', 'cpu', 'gpu'],
  samplingRate: 1000 // Millisecond-level sampling
});

• Metrics: You can monitor multiple metrics simultaneously, including memory usage, CPU load, and GPU performance.
• Sampling Rate: The sampling rate can be adjusted to balance between performance impact and granularity of data.

2. Full-Chain Breakpoint System

DevEco Studio 5.0 offers a comprehensive breakpoint system that supports various types of breakpoints to meet different debugging needs.

Breakpoint Type	Applicable Scenario	Shortcut Key
Conditional Breakpoint	Data Filtering	Ctrl + B
Distributed Breakpoint	Cross-Device Debugging	Alt + Shift + B
Memory Snapshot Breakpoint	OOM Issue Tracking	Ctrl + Alt + M

• Conditional Breakpoint: This allows you to set conditions under which the breakpoint should be triggered. For example, you can set a breakpoint to trigger only when a specific variable reaches a certain value.
• Distributed Breakpoint: Useful for debugging applications that run across multiple devices. This type of breakpoint can help you track the flow of data and interactions between devices.
• Memory Snapshot Breakpoint: Helps in tracking down memory leaks and out-of-memory (OOM) issues by capturing the state of memory at specific points.

3. Real-Time UI Debugging Technology

DevEco Studio 5.0 provides real-time UI debugging capabilities that allow developers to dynamically modify component attributes without recompiling the application.

// Dynamically modify component attributes (no recompilation required)
uiInspector.updateComponent('btnSubmit', {
  enabled: true,
  backgroundColor: '#FF0000'
});

• Component ID: Identify the component you want to modify by its unique ID.
• Attributes: Modify attributes such as enabled and backgroundColor directly through the debugging interface.

4. Distributed Debugging Protocol

For applications that involve multiple devices, DevEco Studio 5.0 supports a distributed debugging protocol that allows you to debug across devices seamlessly.

# Example of cross-device debugging command
hdc shell dist debug -devices 0x2341,0x5678 -pkg com.demo.app

• Device IDs: Specify the IDs of the devices you want to debug.
• Package Name: Identify the application package you are debugging.

II. In-Depth Unit Testing Practices

1. Upgraded ArkTS Testing Framework

The ArkTS testing framework in HarmonyOS Next has been significantly upgraded to support modern testing practices, including data-driven testing.

// New data-driven testing (2025 API)
@ParametrizedTest
@ValueSource([1, 5, 10])
async function testVideoPlayQuality(level: number) {
  const result = await videoPlayer.setQuality(level);
  expect(result).toBeGreaterThan(90); // Video quality score threshold
}

• Parametrized Test: This allows you to run the same test with different input parameters, making your tests more comprehensive.
• Value Source: Specifies the list of values to be used as input parameters for the test.

2. Core Testing Type Comparison

Understanding the differences between various testing types helps in choosing the right approach for your specific needs.

Testing Type	Execution Speed	Isolation Level	Applicable Scenario
Unit Testing	0.5s/test case	Method-level	Business logic validation
Component Testing	2s/test case	Component-level	UI interaction validation
Capability Testing	5s/test case	Process-level	System API call validation

• Unit Testing: Fast execution, focused on validating individual methods or functions.
• Component Testing: Medium execution speed, focused on validating interactions within a component.
• Capability Testing: Slower execution, focused on validating interactions with system APIs.

3. Techniques to Improve Testing Coverage

To ensure comprehensive testing, it is essential to measure and improve test coverage.

{
  "testOptions": {
    "coverage": {
      "instrumentation": true,
      "reportFormat": "html" // Generate visual reports
    }
  }
}

• Instrumentation: Enables code coverage instrumentation.
• Report Format: Specifies the format of the coverage report. HTML reports provide a visual representation of coverage data.

III. End-to-End Integration Testing Solution

1. Cross-Device Testing Suite

HarmonyOS Next supports end-to-end testing across multiple devices, ensuring seamless interactions in a multi-device environment.

// Multi-device collaborative testing script
distTestScheduler.execute({
  devices: ['phone', 'watch', 'tv'],
  scenario: 'media_control_flow',
  steps: [
    { device: 'phone', action: 'play_movie' },
    { device: 'tv', action: 'verify_playback' }
  ]
});

• Devices: List of devices involved in the test.
• Scenario: Describes the test scenario.
• Steps: Defines the sequence of actions to be performed on each device.

2. Cloud Testing Service Integration Process

Integrating with cloud testing services allows you to leverage a wide range of devices and environments for comprehensive testing.

graph TD
  A[Local Test Case Development] --> B[Submit to Huawei Cloud Testing Platform]
  B --> C{Automatic Device Pool Allocation}
  C --> D[Execute Compatibility Testing] ---|Mobile/Tablet|
  C --> E[Execute Special Scenario Testing] ---|In - Car/Wearable|

• Local Test Case Development: Develop your test cases locally.
• Submit to Huawei Cloud Testing Platform: Upload your test cases to the cloud platform.
• Automatic Device Pool Allocation: The platform automatically allocates a pool of devices for testing.
• Execute Compatibility Testing: Run compatibility tests on various devices.
• Execute Special Scenario Testing: Test specific scenarios, such as in-car or wearable devices.

3. Performance Benchmark Testing

Performance benchmark testing helps in ensuring that your application meets specific performance criteria.

// Automated Measurement of Launch Time
perfTestRunner.measure(
  'cold_start', 
  { 
    iterations: 10,
    successCondition: 'avg < 1500ms' 
  }
);

• Measure: Specifies the type of performance metric to measure (e.g., cold start time).
• Iterations: Number of times to run the test.
• Success Condition: Defines the condition for a successful test (e.g., average launch time less than 1500ms).

IV. Quality Assurance Best Practices

1. Layered Testing Pyramid

Adopting a layered testing approach ensures comprehensive quality assurance.

qualityGate: {
  unitTestCoverage: 80%,    // Unit Test Coverage
  componentTestCases: 200,  // Number of Component Test Cases
  e2eTestScenarios: 50      // Number of End-to-End Test Scenarios
}

• Unit Test Coverage: Aim for high coverage of unit tests to catch issues early.
• Component Test Cases: Ensure a significant number of component tests to validate UI interactions.
• End-to-End Test Scenarios: Focus on critical end-to-end scenarios to ensure overall application flow.

2. Fault Injection Testing

Fault injection testing helps in preparing your application for unexpected system conditions.

// Simulate System Fault Conditions
faultInjector.trigger('low_memory', {
  level: 'CRITICAL',
  duration: 5000 // Maintain a low-memory state for 5 seconds
});

• Fault Type: Specifies the type of fault to simulate (e.g., low memory).
• Level: Defines the severity of the fault.
• Duration: Specifies how long the fault condition should be maintained.

3. Automated Pipeline Integration

Integrating testing into your CI/CD pipeline ensures that tests are run automatically, reducing the risk of regressions.

# CI/CD Configuration Example (DevCloud)
- stage: Test
  jobs:
    - name: Unit Test
      task: ArkUnitTest@2
      args: --coverage
    - name: E2E Test
      task: DistTest@5
      devicePool: "harmony - os - 4.0"

• Unit Test: Runs unit tests with coverage reporting.
• E2E Test: Executes end-to-end tests using a specified device pool.

Conclusion

Debugging and testing are critical aspects of developing high-quality applications in HarmonyOS Next. By leveraging the powerful tools and practices outlined in this guide, you can ensure that your applications are robust, performant, and reliable. Always follow best practices and continuously improve your testing strategies to meet the evolving needs of your applications. If you have any further questions or need additional assistance, feel free to leave a comment.