Cross-Language Verification Tests

[elfenpiff]

Goal

Ensure that the container StaticVec & StaticString can be used in an inter-process communication context (C++ <-> Rust) without serialization.

Therefore, we require tests that ensure

1. an identical memory layout of that classes

• the order/offsets of the members must be identical
• the size and alignment of the members
• the semantic type of the members (see int64_t vs u64 in the size member)

2. the have the same content contracts

• see StaticString that supports only characters < 128, if one programming language is able to add illegal characters it would break the contract on the other side

Implementation

1. Identifcal memory layout

This requires whitebox testing on C++ and Rust side. We could introduce a testing.hpp file in the C++ library and a new iceoryx2-bb-container-conformance-tests crate on the C++ side.

• Introduce C function that can and return the size, alignment, offset and type of the members and return it
  • for the type we actually need only to know if the m_size variable is an unsigned integer, the rest can be deduced from the size
• Use bindgen and build.rs to generate a rust file to access the testing.hpp functions within a rust test suite
• write integration tests in iceoryx2-bb-container-conformance-tests that uses the testing.hpp functions and compares the layout with the rust counterpart

2. Same content contract

Introduce a new root folder called component-tests and structure it identical to the examples folder.

• component-tests/cxx
• component-tests/rust
• component-tests/e2e-tests

Write a request response process, where the client requests a change in a given container and the server responds with the performed change. See:

• rust: https://github.com/eclipse-iceoryx/iceoryx2/tree/main/examples/rust/request_response
• c++: https://github.com/eclipse-iceoryx/iceoryx2/tree/main/examples/cxx/request_response
  For instance: client add character x to given string, server responds with string and clients prints the result to the console.

The output can be verified with expect like it is done in the cross-language-end-to-end-tests in the examples folder. The character to add request can be parameterized via cli arguments.