Test returning opaque types in CxxVector from C to Rust
diff --git a/tests/ffi/tests.h b/tests/ffi/tests.h
index e1e163d..ed07ce6 100644
--- a/tests/ffi/tests.h
+++ b/tests/ffi/tests.h
@@ -32,6 +32,7 @@
std::unique_ptr<std::vector<uint8_t>> c_return_unique_ptr_vector_u8();
std::unique_ptr<std::vector<double>> c_return_unique_ptr_vector_f64();
std::unique_ptr<std::vector<Shared>> c_return_unique_ptr_vector_shared();
+std::unique_ptr<std::vector<C>> c_return_unique_ptr_vector_opaque();
void c_take_primitive(size_t n);
void c_take_shared(Shared shared);