NOTE: files in src/ are shared with the GRPC project, and maintained there (any changes should be submitted to GRPC instead). These files are copied from GRPC, and work with both the Protobuf and FlatBuffers code generator.
tests/ contains a GRPC specific test, you need to have built and installed the GRPC libraries for this to compile. This test will build using the FLATBUFFERS_BUILD_GRPCTEST option to the main FlatBuffers CMake project.