A protobuf plugin which writes its input out as a file.
You can then use this as a fixture for debugging plugins as a standalone executable.
Build protoc-gen-fixture and put it in your path
Run against your proto file(s): protoc --fixture_out=. my_protofile.proto
By default, protoc-gen-fixture writes to a file in the current working directory called proto.fixture
You can override this with the filename parameter: --fixture_out=filename=path/to/my/file.fixture
In your own plugins, add a flag to allow reading from a file instead of stdin e.g. --fixture=proto.fixture. You can then easily run your plugin in the debugger exactly as it would be run by protoc.