refactor: map instruction/input/output to chat roles

- RolloutGenerator._instruction_to_messages builds system/user/assistant list (instruction->system, input->user, output->assistant), replacing single-user-turn concatenation
- Remove _iter_samples helper; _prepare_prompts zips parallel list-of-strings fields directly per the collate_fn contract
- Tests adopt a system-aware chat template and pin the three-field role mapping
- Drop unused imports caught by ruff F401 (torch.Tensor in scheduler.py, iter_raw_records in pipeline.py, Tuple in evaluate_rouge.py)
This commit is contained in:
2026-07-20 13:55:25 +08:00
parent e8ff7f5321
commit 06eeeead79
6 changed files with 239 additions and 84 deletions
+85 -34
View File
@@ -1,10 +1,4 @@
"""Unit tests for the online rollout module.
Covers :class:`RolloutResult` / :class:`RawRollout`, :class:`BaseRewardModel`,
:class:`RolloutGenerator` (KV-cache-backed via :class:`InferenceScheduler.run_batch`)
and :class:`RolloutRunner` including its internal cache and rollout-interval
trigger logic.
"""
"""Unit tests for the online rollout module."""
import pytest
import torch
@@ -20,26 +14,49 @@ from astrai.trainer.rollout import (
RolloutRunner,
)
_CHAT_TEMPLATE = (
"{% for message in messages %}"
"{% if message['role'] == 'system' %}SYSTEM: {{ message['content'] }}\n{% endif %}"
"{% if message['role'] == 'user' %}USER: {{ message['content'] }}\n{% endif %}"
"{% if message['role'] == 'assistant' %}ASSISTANT: {{ message['content'] }}\n{% endif %}"
"{% endfor %}"
"{% if add_generation_prompt %}ASSISTANT: {% endif %}"
)
class FakeTokenizer:
"""Minimal char-level tokenizer stub for rollout tests.
Vocab: 0 = pad, 1..255 = byte values. ``stop_ids = [2]`` (a fake
EOS) so tests can verify early-stopping behaviour.
"""
"""Minimal stub tokenizer with a chat template for rollout tests."""
stop_ids = [2]
def encode(self, texts, out_ids=True, **_):
def __init__(self):
from astrai.tokenize.chat_template import ChatTemplate
self._chat_template = ChatTemplate.from_string(_CHAT_TEMPLATE)
def encode(self, texts, **_):
if isinstance(texts, str):
texts = [texts]
return [[b for b in t.encode("utf-8")] for t in texts]
def decode(self, ids, skip_special_tokens=True):
out = bytes(b for b in ids if b > 2 or not skip_special_tokens).decode(
"utf-8", errors="ignore"
if isinstance(ids, list):
return bytes(b for b in ids if b > 2).decode("utf-8", errors="ignore")
return str(ids)
def apply_chat_template(
self, messages, tokenize=True, add_generation_prompt=True, **_
):
rendered = self._chat_template.render(
messages=messages, add_generation_prompt=add_generation_prompt
)
return out
if tokenize:
return (
self.encode(rendered)[0]
if isinstance(rendered, str)
else [self.encode(t)[0] for t in rendered]
)
return rendered
class ConstantRewardModel(BaseRewardModel):
@@ -84,10 +101,11 @@ def _make_scheduler(model, tokenizer, max_batch_size=8, max_len=128):
)
def _make_prompt_batch(batch_size=2, prompt_len=6, device="cpu"):
ids = torch.randint(3, 200, (batch_size, prompt_len), device=device)
mask = torch.ones(batch_size, prompt_len, dtype=torch.bool, device=device)
return {"input_ids": ids, "attention_mask": mask}
def _make_instruction_batch(n=2):
"""Build a batch of instruction+input prompts as lists of strings."""
instructions = [f"Tell me about topic {i}" for i in range(n)]
inputs = [f"context {i}" for i in range(n)]
return {"instruction": instructions, "input": inputs}
def test_raw_rollout_fields():
@@ -114,8 +132,6 @@ def test_rollout_result_inherits_raw_rollout_fields():
assert r.rewards.shape == (2, 3)
assert r.prompts.shape == (2, 4)
assert r.responses.shape == (2, 3, 5)
assert r.prompt_texts == []
assert r.response_texts == []
def test_base_reward_model_is_abstract():
@@ -158,9 +174,8 @@ def _make_generator(device, **kw):
def test_rollout_generator_shapes(device):
gen, _ = _make_generator(device, group_size=3, max_tokens=5)
batch = _make_prompt_batch(batch_size=2, prompt_len=4, device=device)
batch = _make_instruction_batch(n=2)
r = gen.generate(batch)
assert r.prompts.shape == (2, 4)
assert r.responses.shape == (2, 3, 5)
assert r.response_mask.shape == (2, 3, 5)
assert r.logprobs_old.shape == (2, 3, 5)
@@ -172,14 +187,12 @@ def test_rollout_generator_shapes(device):
def test_rollout_generator_mask_matches_responses(device):
"""Positions beyond a response's length are pad (mask False)."""
gen, _ = _make_generator(device, group_size=2, max_tokens=6)
batch = _make_prompt_batch(batch_size=2, prompt_len=4, device=device)
batch = _make_instruction_batch(n=2)
r = gen.generate(batch)
for i in range(2):
for g in range(2):
real = r.response_mask[i, g].sum().item()
# Pad positions should be 0
assert r.responses[i, g, real:].sum() == 0
# logprobs after the real tokens are 0 (padding)
if real < r.logprobs_old.size(-1):
assert torch.all(r.logprobs_old[i, g, real:] == 0)
@@ -187,7 +200,7 @@ def test_rollout_generator_mask_matches_responses(device):
def test_rollout_generator_logprobs_are_nonpositive(device):
"""Behaviour-policy logprobs of sampled tokens should be ≤ 0."""
gen, _ = _make_generator(device, group_size=2, max_tokens=4)
batch = _make_prompt_batch(batch_size=1, prompt_len=3, device=device)
batch = _make_instruction_batch(n=1)
r = gen.generate(batch)
for i in range(1):
for g in range(2):
@@ -196,6 +209,45 @@ def test_rollout_generator_logprobs_are_nonpositive(device):
assert torch.all(lp <= 1e-5)
def test_rollout_generator_instruction_role_mapping(device):
"""instruction → system, input → user, output → assistant."""
gen, _ = _make_generator(device, group_size=1, max_tokens=4)
batch = {
"instruction": ["Be helpful"],
"input": ["What is 2+2?"],
"output": ["Four"],
}
r = gen.generate(batch)
text = r.prompt_texts[0]
assert "SYSTEM: Be helpful" in text
assert "USER: What is 2+2?" in text
assert "ASSISTANT: Four" in text
def test_rollout_generator_messages_format(device):
"""Rollout also accepts pre-built messages."""
gen, _ = _make_generator(device, group_size=2, max_tokens=4)
batch = {
"messages": [
[{"role": "user", "content": "Hello"}],
[{"role": "user", "content": "Goodbye"}],
]
}
r = gen.generate(batch)
assert r.responses.shape[0] == 2
assert len(r.prompt_texts) == 2
assert "Hello" in r.prompt_texts[0] or "USER" in r.prompt_texts[0]
def test_rollout_generator_bad_batch_raises(device):
"""Batch without messages or instruction raises a clear error."""
gen, _ = _make_generator(device)
with pytest.raises(
ValueError, match="must contain either 'messages' or 'instruction'"
):
gen.generate({"input_ids": torch.zeros(2, 4, dtype=torch.long)})
def _make_runner(device, **kw):
generator, model = _make_generator(
device,
@@ -217,10 +269,9 @@ def _make_runner(device, **kw):
def test_rollout_runner_shapes(device):
runner, _ = _make_runner(device, group_size=3, max_tokens=5)
batch = _make_prompt_batch(batch_size=2, prompt_len=4, device=device)
batch = _make_instruction_batch(n=2)
r, is_fresh = runner(batch)
assert is_fresh
assert r.prompts.shape == (2, 4)
assert r.responses.shape == (2, 3, 5)
assert r.response_mask.shape == (2, 3, 5)
assert r.rewards.shape == (2, 3)
@@ -232,7 +283,7 @@ def test_rollout_runner_shapes(device):
def test_rollout_runner_cache_returns_stale_flag(device):
runner, _ = _make_runner(device, rollout_interval=10)
batch = _make_prompt_batch(device=device)
batch = _make_instruction_batch()
r1, fresh1 = runner(batch)
r2, fresh2 = runner(batch)
assert r1 is r2
@@ -242,7 +293,7 @@ def test_rollout_runner_cache_returns_stale_flag(device):
def test_rollout_runner_step_triggers_new_rollout(device):
runner, _ = _make_runner(device, rollout_interval=2)
batch = _make_prompt_batch(device=device)
batch = _make_instruction_batch()
r1, fresh1 = runner(batch)
assert fresh1 is True
runner.step()
@@ -259,7 +310,7 @@ def test_rollout_runner_step_triggers_new_rollout(device):
def test_rollout_runner_clear_cache_forces_rerun(device):
runner, _ = _make_runner(device, rollout_interval=100)
batch = _make_prompt_batch(device=device)
batch = _make_instruction_batch()
r1, _ = runner(batch)
runner.clear_cache()
r2, fresh2 = runner(batch)
@@ -269,7 +320,7 @@ def test_rollout_runner_clear_cache_forces_rerun(device):
def test_rollout_runner_step_resets_counter(device):
runner, _ = _make_runner(device, rollout_interval=1)
batch = _make_prompt_batch(device=device)
batch = _make_instruction_batch()
r1, _ = runner(batch)
runner.step()
r2, fresh2 = runner(batch)