If you’re a C++ developer, you know how important it is to test your code thoroughly. Catch2 is a popular testing framework that can help you do just that. But if you’re ready to take your testing skills to the next level, you can use advanced techniques to improve your testing efficiency and effectiveness. In this article, we’ll explore some tips and tricks for Catch2 that can help you become a better tester.
Table of Contents
What is Catch2?
Catch2 is a modern, open-source, C++ unit testing framework. It is easy to use, expressive, and extensible. Catch2 provides a simple and intuitive syntax for writing tests, allowing you to write both readable and maintainable tests.
Catch2 makes it easy to write automated tests for C++ code, allowing developers to ensure their code is working correctly and catch bugs and regressions before they make it into production. The framework provides a range of features, including a powerful assertion macro, automatic test discovery, rich output, a flexible command-line interface, and support for writing parameterized tests.
Catch2 is widely used in the C++ community and is recommended by many developers as a reliable and effective testing framework. It is available under the Boost Software License, a permissive open-source license.
Example unit test
Here’s an example unit test written using Catch2:
#include <catch2/catch.hpp>
// The function we want to test
int add(int a, int b) {
return a + b;
}
// A test case with a single test
TEST_CASE(“Addition works correctly”) {
REQUIRE(add(2, 2) == 4);
REQUIRE(add(-1, 5) == 4);
REQUIRE(add(0, 0) == 0);
}
In this example, we’re testing the add function, which takes two integers and returns their sum. We’ve written a test case called “Addition works correctly” using the TEST_CASE macro, which groups a set of related tests.
We’ve written three tests using the REQUIRE macro within the test case. Each test asserts that a particular input to the add function produces the expected output. If any of the tests fail, Catch2 will report an error and indicate which test(s) failed.
This is just a simple example, but Catch2 supports many more features, such as parameterized tests, fixtures, and sections, which allow you to write more complex and expressive tests.
What is the use of Catch2?
The primary use of Catch2 is to facilitate unit testing in C++ projects. It is a software testing system where individual units or components of a software application are tested in isolation.
Catch2 provides a modern, easy-to-use, expressive testing framework for C++ developers.
Moreover, it offers a simple and intuitive syntax for writing tests. It provides many features, including a powerful assertion macro, automatic test discovery, rich output, a flexible command-line interface, and support for writing parameterized tests.
By using Catch2, C++ developers can write automated tests for their code, ensuring that it works as intended and catching bugs and regressions before they make it into production. Catch2 also promotes writing modular and decoupled code, which can improve the quality and maintainability of the codebase.
In summary, Catch2 is a valuable tool for C++ developers looking to improve the quality and reliability of their software by adopting a testing-driven development approach.
Some key features of Catch2 include:
- A powerful assertion macro that supports both expression-level and message-level assertions.
- Automatic test discovery, which allows you to write tests without having to register them manually
- The rich output makes it easy to see what tests have passed and failed
- A flexible command-line interface that allows you to customize the test execution
- Support for writing parameterized tests, which enable you to run the same test code with different inputs
Catch2 is widely used in the C++ community and is recommended by many developers as a reliable and effective testing framework. It is available under the Boost Software License, a permissive open-source license.
Why Catch2?
Catch2 is a popular, modern, header-only C++ testing framework that is easy to use, flexible, and fast. Here are some reasons why Catch2 is a good choice for testing your C++ code:
- Easy to use: Catch2 provides a simple and intuitive API that does writing and maintaining unit tests easy. Its syntax is designed to be readable and expressive, which helps to reduce the time required to write and debug tests.
- Flexible: Catch2 supports a wide range of test styles, including BDD-style tests, and provides a rich set of macros and assertion functions that can be used to test different types of code, from simple functions to complex object-oriented designs.
- Fast: Catch2 is designed to be fast and efficient regarding runtime performance and development time. Its lightweight and header-only design makes it easy to integrate into your project, and its test runner is optimized for fast test execution.
- Portable: Catch2 is designed to be platform-independent and works on various platforms, including Windows, Linux, and macOS. It also supports a wide range of compilers and builds systems, which makes it easy to use in different development environments.
- Active community: Catch2 has a large and active community of users and contributors, so plenty of support is available for new users. The framework is constantly improved and updated with new features and bug fixes.
Catch2 is a powerful and versatile testing framework well-suited for testing C++ code, whether working on a small project or a large-scale software application.
How to install Catch2?
To install Catch2, you can follow these steps:
- Visit the Catch2 GitHub repository: https://github.com/catchorg/Catch2
- Download the latest release of Catch2 by clicking on the “releases” tab and selecting the most recent version.
- Extract the downloaded file to a folder of your choice.
- Open the command prompt and navigate to the extracted folder.
- Run the following command to build and install Catch2:
cmake -Bbuild -H. -DBUILD_TESTING=OFF -DCMAKE_INSTALL_PREFIX=<installation_folder>
cmake –build build/ –target install
Note: Replace <installation_folder> with the path to the folder where you want to install Catch2. Depending on your system configuration, you may need to run the above command with administrator privileges.
- Verify the installation by compiling and running the Catch2 example tests provided in the Catch2 repository. You can find these in the test folder.
Once installed, you can start using Catch2 by including the catch.hpp header in your C++ code and writing test cases using the Catch2 framework.
Unit Testing is awesome
Unit testing is an excellent technique for software development! It is a software testing technique where individual units or components of a software application are tested in isolation.
Unit testing aims to verify that each unit or component of the software works as intended.
There are many benefits to unit testing.
- Firstly, it can help catch bugs and errors early in development, making them more accessible and cheaper to fix.
- Unit tests can also help ensure that changes to the code base do not introduce new bugs or regressions.
- Additionally, unit tests can serve as documentation, providing examples of how the code should be used and highlighting its expected behavior.
- Unit testing can also improve the quality and maintainability of the code base by encouraging developers to write more modular and decoupled code.
- Breaking the application into smaller units that can be tested in isolation makes it easier to reason about the code’s behavior and make changes without introducing unexpected side effects.
Overall, unit testing is an essential tool for modern software development, and it is widely adopted by development teams worldwide.
Use Sections to Organize Your Tests
One of the most valuable features of Catch2 is the ability to organize your tests into sections. This can be especially helpful when you have a large number of tests or when you want to group related tests. To create a section, use the SECTION macro and name it. You can then add tests to that section using the TEST_CASE macro. This makes it easy to see which tests are related and can help you identify any patterns or issues that may arise.
Here’s an example of using sections to organize tests in Catch2:
#define CATCH_CONFIG_MAIN
#include “catch2/catch.hpp”
int add(int a, int b) {
return a + b;
}
TEST_CASE(“Addition”) {
SECTION(“Positive numbers”) {
REQUIRE(add(2, 2) == 4);
REQUIRE(add(1, 3) == 4);
}
SECTION(“Negative numbers”) {
REQUIRE(add(-2, -2) == -4);
REQUIRE(add(-1, -3) == -4);
}
SECTION(“Mixed sign numbers”) {
REQUIRE(add(-1, 1) == 0);
REQUIRE(add(-5, 7) == 2);
}
}
In this example, a test case called “Addition” contains three sections, each testing a different aspect of the add function. We use the REQUIRE macro within each section to assert the add output for various input values.
By using sections, we can group related tests and make our test cases easier to read and understand. If one section of the test case fails, the other sections will still be run, allowing us to identify multiple issues with our code in a single test run.
To run this example, you can compile and execute the code, as usual, using your preferred C++ compiler. Catch2 will output information about each test case and section, including any failed assertions.
Leverage Generators to Create Test Data
Generators can be a valuable tool for creating test data in software development. A generator is a function that produces a sequence of values, usually in a deterministic or pseudo-random manner. Using a generator, you can create large amounts of test data quickly and easily without generating each value manually.
Here are some ways you can leverage generators to create test data:
- Random data: Use a random number generator to create test data that is entirely unpredictable. For example, you can generate random strings, integers, or floats. This is particularly useful for testing edge cases and boundary conditions.
- Valid data: Use generators to create valid data that conforms to specific rules or constraints. For example, you can make valid email addresses, phone numbers, or dates. This can help you ensure that your software correctly handles input that meets specific criteria.
- Invalid data: Use generators to create invalid data that violates specific rules or constraints. For example, you can create invalid email addresses, phone numbers, or dates. This can help you ensure that your software correctly handles input that fails to meet specific criteria.
- Combinations of data: Use generators to create combinations of different data types. For example, you can generate a list of tuples that contain a name, email address, and phone number. This can help you test how your software handles complex data structures.
- Large data sets: Use generators to create large data sets that can stress test your software. For example, you can generate a list of a million random integers, which can help ensure that your software is optimized for performance and can handle large amounts of data.
In general, generators can be a powerful tool for creating test data to help you ensure your software is robust and reliable. By leveraging generators, you can save time and effort in creating test data while also increasing the quality of your testing.
Catch run/debug configuration
A run/debug configuration is a set of parameters that defines how an application should be executed or debugged in an integrated development environment (IDE) such as IntelliJ IDEA or Eclipse.
A typical run/debug configuration consists of the following:
- The application to be executed or debugged
- The command-line arguments or program arguments to be passed to the application
- The working directory for the application
- Environment variables to be set for the application
- The JVM options for the application
- The logging settings for the application
- The code coverage options for the application
- The test framework options for the application
- The remote debugger settings if the application is running remotely
- Other custom settings specific to the application or the IDE.
Once a run/debug configuration is defined, the IDE can use it to launch the application and provide debugging capabilities such as breakpoints, watches, and variable inspection. This makes it easy for developers to test and debug their code without manually specifying the command-line arguments and other parameters.
Running tests
To run tests using Catch2, you need to follow these steps:
- Write your tests: Write your test cases using the Catch2 test framework. Tests are functions that return void and do not take any arguments. Each test case should use one or more assertions to check that the code under the test behaves correctly.
For example:
#define CATCH_CONFIG_MAIN // This tells Catch to provide a main() – only do this in one cpp file
#include <catch2/catch.hpp>
TEST_CASE(“Addition works correctly”, “[math]”) {
int a = 2;
int b = 3;
REQUIRE(a + b == 5);
}
- Build your tests: Build your test code and link it against the Catch2 library.
- Run your tests: Run the test executable to execute all the test cases. If any assertion fails, Catch2 will report the failure and give you a detailed report of what went wrong.
For example, if you have built your test code into an executable named “test.exe,” you can run the tests by executing the following:
./test.exe
This will execute all the test cases and report the results.
Some Examples Test Cases in BDD (Behaviour Driven Development) style
In Behaviour Driven Development (BDD), the focus is on defining the software system’s behavior from the stakeholders’ perspective. BDD uses a structured language that focuses on the behavior and outcomes of the system.
Here’s an example of how you can write test cases for a login feature in BDD style:
Feature: Login
- To access my account
- As a registered client
- I want to log in to the system
Scenario: Successful login
- Given I am on the login page
- When I enter valid credentials
- And I click the “Login” button
- Then I should be redirected to the home page
Scenario: Invalid username
- Given I am on the login page
- When I enter an invalid username
- And I enter a valid password
- And I click the “Login” button
- Then I should see an error message
Scenario: Invalid password
- Given I am on the login page
- When I enter a valid username
- And I enter an invalid password
- And I click the “Login” button
- Then I should see an error message
Scenario: Locked account
- Given I am on the login page
- When I enter a username that has locked out
- And I enter a valid password
- And I click the “Login” button
Then I should see a message informing me that my account has been locked.
In this example, we have defined a feature called “Login,” which describes the login feature’s behavior from the stakeholders’ perspective.
We then have several scenarios that describe the different behaviors of the login feature, such as successful login, invalid username, invalid password, and locked account.
Each scenario consists of steps describing the user’s actions, such as entering credentials and clicking the “Login” button, and the expected outcomes, such as redirected to the home page or seeing an error message.
However, by writing test cases in BDD style, you can ensure that the software system is developed, focusing on the behavior and outcomes that matter most to the stakeholders.
This can lead to a more user-centric approach to software development, which can improve the quality and usability of the software.
Catch2 vs. Google test
Catch2 and Google Test are both popular testing frameworks for C++. Here are some differences between the two:
Syntax: One of the significant differences between the two frameworks is their syntax. Catch2 uses a “BDD-style” syntax, which stands for “Behavior-Driven Development.
This means the test cases written in a more human-readable format, making them easier to understand.
Google Test, on the other hand, uses a more traditional syntax that is closer to the way unit tests written in other languages.
Ease of Use: Both frameworks are relatively easy to use, but Catch2 may be easier for beginners due to their simpler syntax.
Google Test has more features, which can also make it more complex to set up and use.
Features: Google Test has more features than Catch2, including support for parameterized tests, test fixtures, and death tests.
Catch2 has some of these features but may not be as fully featured as Google Test.
Integration: Both frameworks can integrate with popular build systems like CMake.
But Google Test also integrates with the Google Mock framework for writing mock objects.
In summary, both Catch2 and Google Test are excellent testing frameworks.
But they have different strengths and weaknesses. Catch2 may be easier for beginners, while Google Test has more features for advanced users.
Ultimately, the choice between the two will depend on your specific needs and preferences.
