11-4 Test Best Practices

Key Concepts

• Write Clear and Descriptive Test Names
• Use beforeEach and afterEach for Setup and Teardown
• Isolate Tests with Mocks and Stubs
• Test Edge Cases
• Avoid Overly Complex Tests
• Use Test Coverage Tools
• Run Tests Frequently
• Automate Testing with CI/CD
• Refactor Tests Alongside Code
• Document Test Cases
• Review and Collaborate on Tests

1. Write Clear and Descriptive Test Names

Ensure that test names clearly describe what is being tested. This makes it easier to understand the purpose of each test and helps in debugging.

Example:

        it('should add two numbers correctly', function() {
            expect(add(1, 2)).toBe(3);
        });
    

Imagine test names as chapter titles in a book, each clearly indicating the content within.

2. Use beforeEach and afterEach for Setup and Teardown

Use beforeEach to set up the environment before each test and afterEach to clean up after each test. This ensures that each test runs in a consistent state.

Example:

        describe('Calculator', function() {
            var calculator;
            beforeEach(function() {
                calculator = new Calculator();
            });
            afterEach(function() {
                calculator = null;
            });
            it('should add two numbers', function() {
                expect(calculator.add(1, 2)).toBe(3);
            });
        });
    

Think of beforeEach and afterEach as preparing a stage before a performance and cleaning up afterward.

3. Isolate Tests with Mocks and Stubs

Use mocks and stubs to isolate the code being tested from external dependencies. This ensures that tests focus on the specific functionality being tested.

Example:

        var mockService = jasmine.createSpyObj('mockService', ['getData']);
        mockService.getData.and.returnValue('mockData');
    

Consider mocks and stubs as stand-ins for actors in a movie, allowing the focus to remain on the main character.

4. Test Edge Cases

Test edge cases to ensure that the code handles extreme or unusual inputs correctly. This helps in identifying potential bugs and improving code robustness.

Example:

        it('should handle zero correctly', function() {
            expect(divide(10, 0)).toBe(Infinity);
        });
    

Think of edge cases as testing the limits of a machine, ensuring it performs well under extreme conditions.

5. Avoid Overly Complex Tests

Keep tests simple and focused on a single piece of functionality. Complex tests are harder to understand and maintain.

Example:

        it('should add two numbers', function() {
            expect(add(1, 2)).toBe(3);
        });
    

Consider a complex test as a multi-layered cake. Each layer (test case) should be simple and easy to understand.

6. Use Test Coverage Tools

Use test coverage tools to measure the percentage of code that is covered by tests. This helps in identifying untested parts of the codebase.

Example:

        karma start --coverage
    

Think of test coverage tools as a map that shows which parts of a city (codebase) have been explored (tested) and which parts are still uncharted.

7. Run Tests Frequently

Run tests frequently to catch issues early in the development process. This helps in maintaining code quality and reducing the cost of fixing bugs.

Example:

        npm test
    

Consider running tests frequently as checking the weather daily to stay prepared for any changes.

8. Automate Testing with CI/CD

Automate testing using Continuous Integration/Continuous Deployment (CI/CD) pipelines. This ensures that tests are run automatically with each code change.

Example:

        // Configure CI/CD in your project
    

Think of CI/CD as an assembly line that continuously checks each product (code change) for defects before it moves to the next stage.

9. Refactor Tests Alongside Code

Refactor tests alongside the code to keep them clean and maintainable. This ensures that tests remain effective and easy to understand.

Example:

        // Refactor test code to improve readability and maintainability
    

Consider refactoring tests as keeping a garden well-maintained, ensuring it remains beautiful and functional.

10. Document Test Cases

Document test cases to provide clear instructions on what each test is checking. This helps in understanding the test logic and maintaining the test suite.

Example:

        // Test case: should add two numbers correctly
        it('should add two numbers correctly', function() {
            expect(add(1, 2)).toBe(3);
        });
    

Think of documenting test cases as writing a recipe, ensuring anyone can follow the steps to achieve the desired result.

11. Review and Collaborate on Tests

Review and collaborate on tests with other developers to catch issues and improve test quality. This ensures that tests are robust and effective.

Example:

        // Review and discuss test cases with team members
    

Consider reviewing and collaborating on tests as a group of experts inspecting a product to ensure it meets high standards.