SingletonBase

Make your C++ singletons testable in 2 lines!

Header-only C++ library for testable singletons. Add one macro, get instant testability.

Create a Testable Singleton

#include <PM/SingletonBase.h>

class MySingleton : public PM::SingletonBase<MySingleton> {
    PM_SINGLETON(MySingleton)  // That's it!

public:
    void setValue(int v) { value_ = v; }
    int getValue() const { return value_; }

private:
    int value_ = 0;
};

Write Unit Tests

#include <PM/ScopedSingletonState.h>

void testMySingleton() {
    PM::ScopedSingletonState<MySingleton> scoped;  // Fresh instance

    MySingleton::instance().setValue(42);
    assert(MySingleton::instance().getValue() == 42);
}

No mocking. No setup. Just test directly.

Documentation

docs

Class	Description	Reference
SingletonBase<T>	Testable singleton base	API
ScopedSingletonState<T>	Test instance replacement	API

Advanced topics: Performance, Thread Safety, etc.

🛠️ How to Add to Your Project

Option 1: Manual (Simplest)

1. Copy the include/ folder to your project
2. Add include/ to your compiler's include paths
3. Include headers: #include <PM/SingletonBase.h>

Option 2: CMake (Recommended)

Add this to your CMakeLists.txt:

add_subdirectory(path/to/SingletonBase)
target_link_libraries(your_target PM::SingletonBase)

This automatically adds the include directory and excludes tests from your build.

License

MIT License - Do whatever you want with it! No restrictions, no strings attached.