Component Testing

Which of the following is a recommended practice for writing component tests?

• Test Vue framework features

• Test implementation details directly

• Write clear test descriptions

• 1. Avoid test coverage metrics

Answer explanation

• Correct Answer:
  
  c) Write clear test descriptions

  • 
    Explanation: Writing clear test descriptions helps improve the readability and maintainability of the test suite. It makes it easier for developers to understand the purpose of each test case.

• 
  Incorrect Answers:
  

  • a) Testing Vue framework features: This is not recommended as Vue framework features are already tested by the Vue.js framework itself.

  • b) Test implementation details directly: Testing implementation details tightly couples the tests to the internal workings of the component, making them brittle and hard to maintain.
    

  • d) Avoid test coverage metrics: Test coverage metrics are essential for measuring the effectiveness of your tests and identifying areas that need better coverage.

What should you focus on when writing component tests?

• Testing internal state directly

• Testing implementation details

• Testing behavior, not implementation

• 1. Ignoring test coverage

Answer explanation

• Correct Answer:
  
  c) Testing behavior, not implementation

  • Explanation: Testing behavior ensures that your tests focus on verifying the external behavior of the component, such as user interactions and expected outcomes, rather than its internal implementation details.

• 
  Incorrect Answers:
  

  • a) Testing internal state directly: Testing internal state can lead to tightly coupled tests that are brittle and hard to maintain.
    

  • b) Testing implementation details: Testing implementation details can make tests fragile and prone to breaking with minor changes to the component's code.
    

  • d) Ignoring test coverage: Ignoring test coverage can lead to gaps in test coverage and potentially missed bugs.

Which of the following is a recommended approach for handling external dependencies in component tests?

• Test private methods directly

• Use snapshots for all tests

• Mock external dependencies

• Overcomplicate test setup

Answer explanation

• Mocking external dependencies isolates the component being tested and ensures that tests focus on its behavior rather than relying on the behavior of external dependencies.
  
  Incorrect Answers:

  • a) Test private methods directly: Testing private methods tightly couples tests to the implementation details of the component, making them less maintainable.
    

  • b) Use snapshots for all tests: Snapshots are useful for capturing the output of a component, but they should be used judiciously alongside behavior-driven tests.
    

  • d) Overcomplicate test setup: Overcomplicating test setup can lead to fragile tests that are difficult to understand and maintain.

Which hook should you use for setting up and cleaning up shared resources in tests?

• beforeEach and afterEach hooks

• beforeAll and afterAll hooks

• afterEach and beforeAll hooks

Answer explanation

• Correct Answer:
  
  a) beforeEach and afterEach hooks

  • 
    Explanation: The beforeEach and afterEach hooks are used to set up and clean up shared resources before and after each test case, ensuring that tests are isolated and independent of each other.

• 
  Incorrect Answers:

  • 
    b) beforeAll and afterAll hooks: The beforeAll and afterAll hooks are used to set up and clean up shared resources once before and after all test cases, which can lead to test pollution and unexpected behavior.

  • 
    c) afterEach and beforeAll hooks: Mixing afterEach and beforeAll hooks can lead to unexpected behavior and test pollution, as afterEach is executed after each test case, while beforeAll is executed only once before all test cases.

In Pinia (State Management) testing stores, actions, containing most of the complex logic, are mocked by default.

• TRUE

• FALSE

Which of the following statements correctly describes the expectation set in the Vue.js test code snippet below?

• The `getLinkLibraryOptions` method of the store should be called exactly once in the test.

• The `getLinkLibraryOptions method` of the store should not be called at all in the test.

• The `getLinkLibraryOptions` method of the store should be called at least once in the test.

What is the purpose of snapshots in Vue.js testing?

• Snapshots capture a representation of the component's rendered output, allowing for visual regression testing.

• Snapshots ensure that the component's template syntax is correct and error-free.

• Snapshots are used to mock external dependencies and isolate the component being tested.

• Snapshots automatically generate test cases based on the component's behavior and usage.

What does the following Vue.js testing syntax accomplish?

• It waits for all pending asynchronous operations within the Vue component to complete before continuing with the test.

• It simulates a user interaction with the Vue component, such as clicking a button or entering text into an input field.

• It checks if the Vue component has been mounted and is ready for testing.

• It updates the Vue component's DOM after changes to its state or properties.

Answer explanation

The await wrapper.vm.$nextTick() syntax in Vue.js testing ensures that the Vue component's DOM is updated to reflect any changes to its internal state or properties. This is especially useful when testing asynchronous updates or changes triggered by promises or reactive data. By waiting for the next tick of the event loop, the test ensures that the DOM has been fully re-rendered before proceeding with any assertions or further test steps.

Briefly explain the code shown in the image.

Briefly explain the code shown in the image.