[FR]: Introduction of a New Macro for Static Methods

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Does the feature exist in the most recent commit?

"No, the feature to mock static member functions is not currently implemented in the most recent commit of Google Mock. This proposal aims to extend the functionality of Google Mock by introducing a new macro, MOCK_STATIC_METHOD, to allow for mocking static member functions."

Why do we need this feature?

Static member functions are difficult to mock in Google Mock due to the lack of support for directly mocking static methods. The current workaround involves using friend classes, wrapping static methods in non-static methods, or injecting function pointers. While these approaches can be effective, they add complexity and require altering the code being tested, which is not always feasible or desirable.

Simplified Unit Testing: Static functions, such as logging or configuration management, are commonly used across many parts of an application. Mocking static methods directly would reduce the need for boilerplate code and workarounds, allowing for simpler, more maintainable tests.

Testability of Legacy Code: Static methods are often part of legacy codebases, and being able to mock them would allow testing of such code without the need to refactor or change its structure.

Improved Developer Experience: Developers will benefit from enhanced capabilities in Google Mock, including more powerful mocking of static methods, leading to more efficient and effective unit testing.

Describe the proposal.

The proposed solution involves extending Google Mock to support mocking static member functions, which is a feature currently missing in the framework. Below is a breakdown of the approach to implement this feature:

1. Introduction of a New Macro for Static Methods To allow mocking of static member functions, we introduce a new macro or extension of the existing MOCK_METHOD macro in Google Mock. This new macro will be used to define the behavior of static methods in mock classes.

For example, a new macro MOCK_STATIC_METHOD will be introduced to mock static methods, similarly to how instance methods are mocked.

` // Example mock for static method in Google Mock class MockLogger { public:

// New static method mock macro for static methods:

MOCK_STATIC_METHOD(void, logInfo, (const std::string&), ());
MOCK_STATIC_METHOD(void, logWarning, (const std::string&), ());
MOCK_STATIC_METHOD(void, logError, (const std::string&), ());

}; ` 2. Internals: Static Method Invocation Tracking Internally, Google Mock will need to manage the state of static method invocations. Since static methods are not part of an instance, they cannot be intercepted by normal polymorphic behavior However, Google Mock can track these calls by employing a proxy mechanism or wrapper classes behind the scene

Here’s a high-level explanation of the approach:

Static Proxy/Wrapper: Internally create a proxy or wrapper that allows Google Mock to intercept calls to static methods. This proxy can either redirect static method calls or replace the static method calls with calls to a mocked version.

Tracking Static Invocations: For each static method call, Google Mock will store the invocation details (e.g., arguments, times called) and compare it against the expectations set up in the test. This would work similarly to how instance methods are mocked.

Implementation Strategy The implementation can proceed as follows:

Extend the MOCK_METHOD Macro: Modify the existing MOCK_METHOD macro to introduce a new MOCK_STATIC_METHOD macro that allows static methods to be mocked.

Implement Static Method Proxy: Internally implement a static method proxy or wrapper that handles static method invocations and routes them through Google Mock’s internal mock tracking system.

Update Google Mock Invocation Tracking: Modify the invocation tracking system to handle static methods, ensuring that they are tracked and that their expectations are verified correctly.

. Benefits of This Approach Non-Intrusive: This approach allows developers to mock static methods without altering the production code. There is no need for changes such as converting static methods to non-static or creating additional wrapper classes.

Backward Compatibility: The new feature would be implemented without disrupting existing functionality. Tests that do not require mocking static methods will continue to work as they did previously.

Simpler Tests for Static Method Usage: This approach reduces the complexity of writing tests for classes that rely on static methods, making the unit testing process more efficient.

I dont know whether this feature will be implemented or not but i feels the need of this as I have to write wrappers on my static functions for unit testing.

Is the feature specific to an operating system, compiler, or build system version?

"No, this feature is not specific to any particular operating system, compiler, or build system version. The proposed functionality is intended to work across all platforms that support the Google Mock framework and its dependencies, such as GCC, Clang, MSVC, and CMake."