These tests validate that a Nim FFI library exported with nim-ffi's C++ codegen is usable from a real C++ consumer. They drive the my_timer example through its auto-generated my_timer.hpp bindings (constructor, sync method, async methods, complex types with optional fields, multiple contexts, error propagation, async pipelines, short-lived-thread stress, concurrent hammer) and assert the round-tripped values. The CrossLibrary test additionally loads examples/echo's echo.hpp alongside the timer to prove two independent nim-ffi libraries coexist in one process with no symbol clash and no shared global state.

Layout

The suite reuses the generated bindings instead of duplicating the Nim build glue:

CMakeLists.txt — add_subdirectorys both examples/timer/cpp_bindings (compiles libmy_timer, exposes my_timer_headers) and examples/echo/cpp_bindings (compiles libecho, exposes echo_headers). Fetches GoogleTest and registers tests with CTest via gtest_discover_tests.
test_timer_e2e.cpp — the test cases.

Running

# 1. Generate the C++ bindings for both example libraries
nimble genbindings_cpp        # → examples/timer/cpp_bindings/
nimble genbindings_cpp_echo   # → examples/echo/cpp_bindings/

# 2. Configure + build + run the tests
cmake -S tests/e2e/cpp -B tests/e2e/cpp/build
cmake --build tests/e2e/cpp/build
ctest --test-dir tests/e2e/cpp/build --output-on-failure