Measuring Test Coverage

1. Introduction

Test coverage is a critical aspect of software testing that measures how much of the code is tested by automated tests. High test coverage can lead to fewer bugs and issues in production.

2. Key Definitions

3. Types of Coverage

4. Measuring Coverage

To measure test coverage, you can use various tools depending on the programming language. For JavaScript, tools like Jest, Istanbul, and Mocha are commonly used. Below is a basic example using Jest.

const add = (a, b) => a + b;

module.exports = add;

const add = require('./add');

test('adds 1 + 2 to equal 3', () => {
    expect(add(1, 2)).toBe(3);
});

To run tests and measure coverage, use the command:

jest --coverage

This will generate a coverage report that shows which lines were executed during tests.

5. Best Practices

• Write tests for all new features.
• Regularly measure coverage to identify gaps.
• Aim for high statement and branch coverage, but focus on meaningful tests.
• Use coverage reports to guide your testing efforts.
• Combine automated tests with manual testing for comprehensive coverage.

6. FAQ