unsloth/tests/python/test_change_system_message.py
Daniel Han 50b9deacb0
Trim comments in tests (#13844)
Comment and docstring changes only, in test files, split out of #12968 so the test-only part can merge first.
2026-10-15 05:30:27 -07:00

78 lines
2.8 KiB
Python

import ast
import re
import types
from pathlib import Path
import pytest
def _load_change_system_message():
# Extract _change_system_message without importing unsloth (needs unsloth_zoo / a GPU).
source = Path(__file__).parents[2] / "unsloth" / "chat_templates.py"
tree = ast.parse(source.read_text(encoding = "utf-8"))
funcs = [
node
for node in tree.body
if isinstance(node, ast.FunctionDef)
and node.name in ("_change_system_message", "_escape_jinja_literal")
]
namespace = {
"re": re,
"logger": types.SimpleNamespace(warning_once = lambda *a, **k: None),
"DEFAULT_SYSTEM_MESSAGE": {"unsloth": "You are a helpful assistant to the user"},
}
module = ast.Module(body = funcs, type_ignores = [])
ast.fix_missing_locations(module)
exec(compile(module, str(source), "exec"), namespace)
return namespace["_change_system_message"]
CUSTOM = "mycustom" # no predefined default
def test_custom_template_fills_placeholder():
fn = _load_change_system_message()
template, used = fn("System: {system_message}\nUser:", CUSTOM, "You are a pirate")
assert template == "System: You are a pirate\nUser:"
assert "{system_message}" not in template
assert used == "You are a pirate"
def test_custom_template_preserves_backslashes():
# str.replace, not re.sub: backslashes in messages must be inserted verbatim.
fn = _load_change_system_message()
for msg in (r"C:\Users\me", r"\frac{a}{b}", r"see \1 here"):
template, used = fn("System: {system_message}", CUSTOM, msg)
assert template == f"System: {msg}"
assert used == msg
def test_custom_template_requires_system_message():
fn = _load_change_system_message()
with pytest.raises(ValueError):
fn("System: {system_message}", CUSTOM, None)
def test_custom_template_without_placeholder_unchanged():
fn = _load_change_system_message()
template, used = fn("System: fixed", CUSTOM, "ignored")
assert template == "System: fixed"
def test_predefined_template_uses_default_then_override():
fn = _load_change_system_message()
t1, u1 = fn("System: {system_message}", "unsloth", None)
assert t1 == "System: You are a helpful assistant to the user"
t2, u2 = fn("System: {system_message}", "unsloth", "Custom override")
assert t2 == "System: Custom override"
assert u2 == "Custom override"
def test_predefined_template_escapes_but_custom_does_not():
# Predefined templates escape {system_message} inside a Jinja literal; custom ones keep it raw.
fn = _load_change_system_message()
msg = """it's a \\test "x"."""
predefined, used = fn("System: {system_message}", "unsloth", msg)
assert predefined == """System: it\\'s a \\\\test \\"x\\"."""
assert used == msg
assert fn("System: {system_message}", CUSTOM, msg)[0] == f"System: {msg}"