GuildLM · go-test

Name: go-test
Rating: 2.5 (34 reviews)

A small, sharp Go testing specialist from the GuildLM Code Guild.

go-test writes thorough, table-driven Go tests with real assertions and meaningful edge cases — the kind of tests that actually fail when the code is wrong. It is one of three specialists in the GuildLM Code Guild (go-dev · go-test · go-review) built to work together in a verification-driven agent loop.

Why a dedicated test model? Across every GuildLM experiment, writing tests is the one job where targeted fine-tuning clearly beats the base. On a mutation benchmark — inject a bug, does the generated test catch it? — go-test catches 14/18 (78%) versus 7/18 (39%) for the untuned base. It catches twice as many real bugs as the model it's built on. Test-writing is genuinely where specialization pays. See the research log, Report #2.

Why this isn't "just Qwen with a name"

go-test is a fused, standalone model (no separate adapter) with its own identity — ask who it is and it answers GuildLM go-test. It is an honest Apache-2.0 derivative of Qwen2.5-Coder-7B-Instruct, fine-tuned for one craft: testing Go.

What it's for

Generating *_test.go files: table-driven cases, sub-tests, httptest, sync/atomic for concurrency checks.
Covering the edges a tired human skips: empty input, zero values, negatives, inverted bounds, error paths.
Acting as the testing role inside the GuildLM Builder, so the code that go-dev writes is held to a real, executable contract.

Benchmarks

Measured locally with the real Go toolchain — tests are scored by whether they compile, assert, and catch injected mutations, not by an LLM judge.

Benchmark	Metric	go-test	base 7B
crucible `go_test_bench` (18 mutations)	bug-catch@1	14/18 · 78%	7/18 · 39%

This is the GuildLM specialist where the fine-tuning win is real, large, and repeatable — go-test catches 2× the injected bugs of its base. A guard in the Builder also rejects trivially-passing tests (no assertions), so its output is held to a real bar in the loop.

Quickstart

Apple Silicon (MLX)

bash

pip install mlx-lm
python -m mlx_lm generate --model guildlm/go-test \
  --prompt "Write table-driven Go tests for func Clamp(x, lo, hi int) int covering below/inside/above range and inverted bounds." \
  --max-tokens 400

Ollama (GGUF)

ollama run guildlm/go-test "Write httptest-based tests for a POST /echo JSON endpoint built with newMux()."

Inside the agent loop (recommended)

bash

python -m mlx_lm server --model guildlm/go-test --port 8081
guildlm-build --spec specs/myservice.yaml --out ./out \
  --base-url http://localhost:8080/v1 \
  --test-model guildlm/go-test --test-base-url http://localhost:8081/v1 \
  --candidates 3

Prompting

Trained with the system prompt:

You are GuildLM go-test, a Go testing specialist from the GuildLM Code Guild.

Give it a function signature or an implementation and ask for tests. It defaults to table-driven style with explicit t.Errorf/t.Fatalf assertions.

The Guild

Specialist	Job
go-dev	writes the implementation
go-test	writes thorough table-driven tests
go-review	audits for bugs a green build hides

Agent loop: https://github.com/guildlm/builder
Research log: https://guildlm.github.io/research/

License & attribution

Apache-2.0, inherited from Qwen2.5-Coder-7B-Instruct (© Alibaba Cloud). GuildLM fine-tuning, identity, and packaging under the same license. Trained locally on Apple Silicon with MLX — total cloud spend: $0.