unsloth/studio/backend/tests/test_diffusion_backend.py

306 lines
11 KiB
Python

# SPDX-License-Identifier: AGPL-3.0-only
# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
"""CPU-only unit tests for the diffusion backend.
The family helpers are pure functions, tested directly. The backend lifecycle is
exercised with ``torch`` / ``diffusers`` stubbed via ``sys.modules`` so no real
GPU, weights, or network access is needed (sub-second, CI-friendly).
"""
from __future__ import annotations
import sys
import types
import pytest
from core.inference.diffusion import (
DiffusionBackend,
_base_file_downloaded,
)
from core.inference.diffusion_families import (
detect_family,
resolve_base_repo,
resolve_local_gguf_child,
)
# Pure family helpers
def test_detect_family_from_repo_id():
assert detect_family("unsloth/Z-Image-Turbo-GGUF").name == "z-image"
assert detect_family("unsloth/Z-Image-GGUF").name == "z-image"
assert detect_family("meta-llama/Llama-3-8B") is None
assert detect_family("unsloth/FLUX.2-klein-4B-GGUF") is None # not in the MVP family table
def test_detect_family_override():
assert detect_family("local/path", override = "z-image").name == "z-image"
assert detect_family("local/path", override = "zimage").name == "z-image"
assert detect_family("local/path", override = "not-a-family") is None
def test_resolve_base_repo():
fam = detect_family("x", override = "z-image")
assert resolve_base_repo(fam, None) == fam.base_repo
assert resolve_base_repo(fam, " ") == fam.base_repo
assert resolve_base_repo(fam, "custom/base") == "custom/base"
def test_resolve_local_gguf_child(tmp_path):
(tmp_path / "model.gguf").write_bytes(b"x")
assert resolve_local_gguf_child(tmp_path, "model.gguf") == (tmp_path / "model.gguf").resolve()
with pytest.raises(ValueError):
resolve_local_gguf_child(tmp_path, "/etc/passwd")
with pytest.raises(ValueError):
resolve_local_gguf_child(tmp_path, "../secret.gguf")
with pytest.raises(ValueError):
resolve_local_gguf_child(tmp_path, "..\\secret.gguf")
with pytest.raises(FileNotFoundError):
resolve_local_gguf_child(tmp_path, "missing.gguf")
def test_resolve_local_gguf_child_blocks_symlink_escape(tmp_path):
outside = tmp_path / "outside.gguf"
outside.write_bytes(b"secret")
repo = tmp_path / "repo"
repo.mkdir()
try:
(repo / "model.gguf").symlink_to(outside)
except (OSError, NotImplementedError):
pytest.skip("symlinks not supported on this platform")
with pytest.raises(ValueError):
resolve_local_gguf_child(repo, "model.gguf")
# Stubbed runtime for backend lifecycle
class _FakeDtype:
def __init__(self, name: str) -> None:
self._name = name
def __repr__(self) -> str:
return f"torch.{self._name}"
__str__ = __repr__
class _FakeGenerator:
def __init__(self, device = None) -> None:
self.device = device
self.manual = None
def seed(self) -> int:
return 4242
def manual_seed(self, value: int):
self.manual = value
return self
class _FakeImage:
"""Stand-in for a generated PIL image (the route persists it; here we only
count how many come back)."""
class _FakePipe:
def __init__(self) -> None:
self.moved_to = None
self.offloaded = False
self.last_kwargs = None
def to(self, device):
self.moved_to = device
return self
def enable_model_cpu_offload(self) -> None:
self.offloaded = True
def __call__(self, **kwargs):
self.last_kwargs = kwargs
n = kwargs.get("num_images_per_prompt", 1)
return types.SimpleNamespace(images = [_FakeImage() for _ in range(n)])
class _FakePipeline:
last: dict = {}
@classmethod
def from_pretrained(cls, base, **kwargs):
_FakePipeline.last = {"base": base, **kwargs}
return _FakePipe()
class _FakeTransformer:
last: dict = {}
@classmethod
def from_single_file(cls, path, **kwargs):
_FakeTransformer.last = {"path": path, **kwargs}
return object()
@pytest.fixture
def fake_runtime(monkeypatch):
torch = types.ModuleType("torch")
torch.bfloat16 = _FakeDtype("bfloat16")
torch.float16 = _FakeDtype("float16")
torch.float32 = _FakeDtype("float32")
torch.Generator = _FakeGenerator
torch.cuda = types.SimpleNamespace(is_available = lambda: False)
torch.backends = types.SimpleNamespace(mps = None)
diffusers = types.ModuleType("diffusers")
diffusers.GGUFQuantizationConfig = lambda compute_dtype = None: ("quant", compute_dtype)
diffusers.ZImagePipeline = _FakePipeline
diffusers.ZImageTransformer2DModel = _FakeTransformer
monkeypatch.setitem(sys.modules, "torch", torch)
monkeypatch.setitem(sys.modules, "diffusers", diffusers)
# The backend imports clear_gpu_cache by reference; no-op it so unload doesn't
# run real hardware detection against the stubbed torch.
monkeypatch.setattr("core.inference.diffusion.clear_gpu_cache", lambda: None)
_FakePipeline.last = {}
_FakeTransformer.last = {}
yield
def test_load_generate_unload_gguf(fake_runtime, tmp_path):
(tmp_path / "model.gguf").write_bytes(b"weights")
backend = DiffusionBackend()
status = backend.load_pipeline(
str(tmp_path),
gguf_filename = "model.gguf",
base_repo = "base/repo",
family_override = "z-image",
)
assert status["loaded"] is True
assert status["family"] == "z-image"
assert status["base_repo"] == "base/repo"
assert status["device"] == "cpu"
assert status["dtype"] == "float32"
assert status["cpu_offload"] is False
# Transformer built from the local GGUF, pipeline assembled from the base repo.
assert _FakeTransformer.last["path"] == str((tmp_path / "model.gguf").resolve())
assert _FakeTransformer.last["subfolder"] == "transformer"
assert _FakePipeline.last["base"] == "base/repo"
assert "transformer" in _FakePipeline.last
gen = backend.generate(prompt = "a sloth", width = 512, height = 512, steps = 4, guidance = 3.0)
assert gen["seed"] == 4242 # random seed reported back
assert gen["repo_id"] == str(tmp_path) # echoed so the route can record the model
assert len(gen["images"]) == 1 # PIL images handed to the route for persistence
gen2 = backend.generate(prompt = "again", seed = 99)
assert gen2["seed"] == 99
# batch_size produces that many images in one call, all sharing the seed.
batch = backend.generate(prompt = "batch", seed = 7, batch_size = 3)
assert len(batch["images"]) == 3 and batch["seed"] == 7
assert backend.unload()["loaded"] is False
assert backend.is_loaded is False
def test_cpu_offload_ignored_off_cuda(fake_runtime, tmp_path):
(tmp_path / "model.gguf").write_bytes(b"x")
backend = DiffusionBackend()
status = backend.load_pipeline(
str(tmp_path),
gguf_filename = "model.gguf",
family_override = "z-image",
base_repo = "base/repo",
cpu_offload = True,
)
# No CUDA in the stub, so offload is not engaged.
assert status["cpu_offload"] is False
def test_generate_without_load_raises(fake_runtime):
backend = DiffusionBackend()
with pytest.raises(RuntimeError):
backend.generate(prompt = "x")
def test_load_without_gguf_raises():
backend = DiffusionBackend()
with pytest.raises(ValueError):
backend.load_pipeline("unsloth/Z-Image-Turbo-GGUF") # no gguf_filename
def test_load_unknown_family_raises():
backend = DiffusionBackend()
with pytest.raises(ValueError):
backend.load_pipeline("some/unrecognised-repo", gguf_filename = "x.gguf")
# load_progress state machine (no threads / network / real cache)
from core.inference.diffusion import _LoadingState, _LoadState # noqa: E402
def test_load_progress_idle_and_ready():
backend = DiffusionBackend()
assert backend.load_progress()["phase"] is None
backend._state = _LoadState(object(), None, "r", "b", "cpu", "float32", False)
assert backend.load_progress()["phase"] == "ready"
def test_load_progress_error():
backend = DiffusionBackend()
backend._loading = _LoadingState(repo_id = "r", base_repo = "b", error = "boom")
p = backend.load_progress()
assert p["phase"] == "error" and p["error"] == "boom"
def test_load_progress_downloading_then_finalizing(monkeypatch):
backend = DiffusionBackend()
backend._loading = _LoadingState(repo_id = "r", base_repo = "b", expected_bytes = 1000)
monkeypatch.setattr(DiffusionBackend, "_cache_bytes", staticmethod(lambda repo: 150))
p = backend.load_progress()
assert p["phase"] == "downloading"
assert p["bytes_downloaded"] == 300 # summed across repo + base
assert abs(p["fraction"] - 0.3) < 1e-9
monkeypatch.setattr(DiffusionBackend, "_cache_bytes", staticmethod(lambda repo: 500))
assert backend.load_progress()["phase"] == "finalizing" # 1000/1000
def test_base_file_downloaded_excludes_undownloaded():
# Counted: the pipeline manifest + component subfolders from_pretrained fetches.
assert _base_file_downloaded("model_index.json")
assert _base_file_downloaded("text_encoder/model-00001-of-00003.safetensors")
assert _base_file_downloaded("vae/diffusion_pytorch_model.safetensors")
# Excluded: the GGUF supplies the transformer; docs/assets and top-level files
# are never downloaded, so counting them would peg the bar short of 100%.
assert not _base_file_downloaded("transformer/diffusion_pytorch_model-00001-of-00003.safetensors")
assert not _base_file_downloaded("assets/Z-Image-Gallery.pdf")
assert not _base_file_downloaded("README.md")
assert not _base_file_downloaded(".gitattributes")
def test_load_progress_fraction_clamped(monkeypatch):
# The cache scan can exceed the estimate (e.g. a second cached quant); the
# reported fraction must still clamp to 1.0 rather than overshoot.
backend = DiffusionBackend()
backend._loading = _LoadingState(repo_id = "r", base_repo = "b", expected_bytes = 1000)
monkeypatch.setattr(DiffusionBackend, "_cache_bytes", staticmethod(lambda repo: 900))
p = backend.load_progress() # summed 1800 > expected 1000
assert p["phase"] == "finalizing"
assert p["fraction"] == 1.0
assert p["bytes_downloaded"] == 1000 # clamped to the estimate
def test_begin_load_rejects_concurrent(monkeypatch):
backend = DiffusionBackend()
monkeypatch.setattr(DiffusionBackend, "_estimate_download_bytes", staticmethod(lambda *a, **k: 0))
# Block the spawned worker so the load stays "in progress".
monkeypatch.setattr(DiffusionBackend, "load_pipeline", lambda self, **k: __import__("time").sleep(0.2))
backend.begin_load("unsloth/Z-Image-Turbo-GGUF", gguf_filename = "z-image-turbo-Q4_K_S.gguf")
with pytest.raises(RuntimeError):
backend.begin_load("unsloth/Z-Image-Turbo-GGUF", gguf_filename = "z-image-turbo-Q4_K_S.gguf")