* Implements mocking of runtime apis
This pr adds support for easily mock runtime api implementations for
tests by using the `mock_impl_runtime_apis!` macro. The syntax is
similar to `impl_runtime_apis!`. The mocked implementation automatically
implements `ApiExt`, `ApiErrorExt` and `Core` as these are required by
the runtime api traits, but not required in tests or only a subset of them.
* Fix warnings
* Update primitives/api/proc-macro/src/utils.rs
Co-Authored-By: Nikolay Volf <nikvolf@gmail.com>
* Review feedback
Co-authored-by: Nikolay Volf <nikvolf@gmail.com>