Unit Test Configuration Values for Go

[connerohnesorge]

Add Unit Testing for V1 Nix Config - Go Protocol Buffer Plugins

Overview

Implement comprehensive unit testing using nix-unit to ensure our Go protocol buffer configuration maintains a consistent public interface and correctly maps to protoc plugin names.

Requirements

Core Testing Goals

• Verify that public interface remains stable across changes
• Ensure plugin names match their corresponding protoc-gen plugin names
• Test all configurable values for Go protocol buffer plugins

Plugin Configuration Testing

Each protoc-gen plugin must be testable for:

• Enablement: Each plugin should have an enable flag that can be toggled
• Package Override: Each plugin should allow package redefinition for custom implementations

Implementation Details

Testing Framework

Use nix-unit with flake-parts integration:

perSystem = { ... }: {
  nix-unit.inputs = {
    # NOTE: nixpkgs-lib follows rule is currently required
    inherit (inputs) nixpkgs flake-parts nix-unit;
  };
  
  # Tests for Go protoc plugins
  nix-unit.tests = {
    # Test plugin enablement (default: disabled)
    "protoc-gen-go-enable" = {
      expr = self.mkBufrnixPackage.go.enable;
      expected = false;
    };
    
    # Test default package assignment
    "protoc-gen-go-package" = {
      expr = self.mkBufrnixPackage.go.package;
      expected = pkgs.protoc-gen-go;
    };
    
    # Additional plugin tests would follow the same pattern:
    # "protoc-gen-go-grpc-enable" = { ... };
    # "protoc-gen-go-grpc-package" = { ... };
  };
};

Test Coverage Requirements

Each test should validate:

1. Plugin Name Mapping: Test values should correspond to actual protoc plugin names
2. Default State: Plugins should be disabled by default (enable = false)
3. Package Resolution: Default packages should point to correct nixpkgs derivations
4. Interface Consistency: Public API should remain stable

Acceptance Criteria

• All Go protoc-gen plugins have corresponding enable/package tests
• Test names match protoc plugin naming conventions
• Default configurations are properly tested
• Tests pass in CI/CD pipeline
• Documentation updated with testing approach

Additional Notes

This testing infrastructure will serve as a foundation for ensuring backward compatibility and preventing regressions in the public interface of our Nix Go configuration.

[connerohnesorge]

https://nix-community.github.io/nix-unit/examples/flake-parts.html

[connerohnesorge]

might be nice/useful to inline everything during development here