8 Test Coverage Techniques

1. Product Coverage

The Product test coverage technique measures the various parts or modules of the tested application.

Example: In a "shopping cart" application, product coverage would involve testing the basic add/remove item functionality and scenarios like handling a cart with a maximum number of items or how the cart behaves when an item is out of stock.

2. Risk Coverage

This test coverage technique is all about identifying the risk elements (within any application) and completely testing them.

Example: Risk element in an eCommerce app is whether shoppers can connect to the third-party payment gateway and complete their payments successfully. Based on the risk assessments, four scenarios are likely to develop, namely:

3. Requirements Coverage

The requirements test coverage technique tests if the product or application meets the customer requirements. This technique bases itself on the philosophy that "high-quality products are useless if they don't serve user requirements." In essence, this technique measures if the final product contains all the "promised" functionalities and meets the customer's listed requirements.

Example: If a customer requirement for a travel booking app includes a feature for multi-city flight bookings, requirements coverage would test whether the app allows users to book flights with multiple stopovers, as promised in the app's feature list.

4. Compatibility Coverage

Compatibility test coverage ensures that the testing checks the final application across all supported devices and browsers. To that end, this technique aims to reduce the product's compatibility-related problems.

Example: Testing a website across browsers (like Chrome, Firefox, Safari) and devices (like smartphones, tablets, PCs) to ensure consistent functionality and layout, regardless of how users access the site.

5. Branch Coverage

Branch coverage ensures every possible pathway in your code is tested at least once. It's crucial for uncovering hidden errors and ensuring all code branches are error-free.

Example: In a weather forecasting app, if there's a condition that checks the temperature to display 'Hot' or 'Cold', branch coverage would test both scenarios: one where the temperature is above the threshold (leading to 'Hot') and one where it's below (leading to 'Cold').

6. Code Coverage

Code coverage measures the percentage of your code that is tested, helping to identify untested parts. It's a key metric for understanding the extent of your testing efforts.

Example: In a calculator app, if there are functions for addition, subtraction, multiplication, and division, code coverage would involve creating tests that exercise each function to ensure all code is tested.

7. Statement Coverage

Statement coverage checks that every line of code is executed during testing. This technique is essential for uncovering bugs and ensuring comprehensive code testing.

Example: For a document editing tool, statement coverage would ensure that every feature (like text formatting, image insertion, page setup) is tested at least once to check all lines of code are executed during testing.

8. Boundary Values Coverage

Boundary values coverage focuses on testing the extreme limits of input ranges. It's vital to catch errors at the edges of input conditions, ensuring robust data handling.

Example: In an online form that accepts age input, boundary value coverage would test the limits, such as entering the minimum allowed age, maximum allowed age, and invalid ages (like negative numbers or excessively high ages) to ensure proper handling of edge cases.