minimind/course/impl/tests/test_lora_injection.py

94 lines
2.6 KiB
Python

"""Alignment tests for lesson 19 LoRA injection flow.
Run after implementing:
python course/impl/tests/test_lora_injection.py
"""
from __future__ import annotations
import sys
from pathlib import Path
import torch
from torch import nn
ROOT = Path(__file__).resolve().parents[3]
sys.path.insert(0, str(ROOT))
from course.impl.core.lora import ( # noqa: E402
LoRALinear,
apply_lora_to_linear_layers,
lora_state_dict,
mark_only_lora_as_trainable,
)
def max_abs_diff(a: torch.Tensor, b: torch.Tensor) -> float:
return (a - b).abs().max().item()
def test_injection_preserves_initial_output() -> None:
torch.manual_seed(42)
model = nn.Sequential(
nn.Linear(4, 4, bias=False),
nn.Linear(4, 3, bias=False),
nn.Sequential(nn.Linear(3, 3, bias=False)),
)
x = torch.randn(2, 4)
with torch.no_grad():
before = model(x)
injected = apply_lora_to_linear_layers(model, rank=2, alpha=2.0, dropout=0.0, square_only=True)
print(f"injected_lora_layers={injected}")
assert injected == 2
assert isinstance(model[0], LoRALinear)
assert isinstance(model[1], nn.Linear)
assert isinstance(model[2][0], LoRALinear)
with torch.no_grad():
after = model(x)
diff = max_abs_diff(before, after)
print(f"initial_output_max_abs_diff={diff:.12f}")
assert diff < 1e-6
def test_lora_trainable_and_state_dict_after_injection() -> None:
model = nn.Sequential(
nn.Linear(4, 4, bias=False),
nn.Linear(4, 3, bias=False),
nn.Sequential(nn.Linear(3, 3, bias=False)),
)
apply_lora_to_linear_layers(model, rank=2, alpha=2.0, dropout=0.0, square_only=True)
lora_params = mark_only_lora_as_trainable(model)
trainable_names = [name for name, param in model.named_parameters() if param.requires_grad]
print(f"trainable_names={trainable_names}")
assert trainable_names == ["0.A.weight", "0.B.weight", "2.0.A.weight", "2.0.B.weight"]
assert list(lora_params) == [
model[0].A.weight,
model[0].B.weight,
model[2][0].A.weight,
model[2][0].B.weight,
]
state = lora_state_dict(model)
print(f"lora_state_keys={sorted(state.keys())}")
assert sorted(state.keys()) == ["0.A.weight", "0.B.weight", "2.0.A.weight", "2.0.B.weight"]
def main() -> None:
try:
test_injection_preserves_initial_output()
test_lora_trainable_and_state_dict_after_injection()
except NotImplementedError as exc:
raise SystemExit(f"TODO not implemented yet: {exc}") from exc
print("lora_injection=passed")
if __name__ == "__main__":
main()