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LangBot/tests/unit_tests/workflow/test_safe_eval.py
Typer_Body cb0cc4d06a cold
2026-06-05 21:20:46 +08:00

230 lines
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Python

"""Tests for the safe expression evaluator that replaced eval().
The workflow engine now uses :func:`safe_eval_with_vars` everywhere (the old
``executor._safe_eval`` helper was removed to eliminate duplication). These
tests exercise that single, shared evaluator.
"""
import sys
import os
import pytest
# Add project root to path
sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..', '..', 'src'))
from langbot.pkg.workflow.safe_eval import safe_eval_with_vars
def _safe_eval(expr):
"""Backwards-compatible shim: evaluate an expression with no bound vars."""
return safe_eval_with_vars(expr)
class TestSafeEvalLiterals:
"""Test literal value evaluation."""
def test_integer(self):
assert _safe_eval("42") == 42
def test_negative_integer(self):
assert _safe_eval("-5") == -5
def test_float(self):
assert _safe_eval("3.14") == pytest.approx(3.14)
def test_string(self):
assert _safe_eval('"hello"') == "hello"
def test_single_quoted_string(self):
assert _safe_eval("'world'") == "world"
def test_true(self):
assert _safe_eval("True") is True
def test_false(self):
assert _safe_eval("False") is False
def test_none(self):
assert _safe_eval("None") is None
class TestSafeEvalComparisons:
"""Test comparison operators."""
def test_eq_true(self):
assert _safe_eval("1 == 1") is True
def test_eq_false(self):
assert _safe_eval("1 == 2") is False
def test_neq(self):
assert _safe_eval("1 != 2") is True
def test_gt(self):
assert _safe_eval("3 > 2") is True
def test_gte(self):
assert _safe_eval("3 >= 3") is True
def test_lt(self):
assert _safe_eval("1 < 2") is True
def test_lte(self):
assert _safe_eval("2 <= 2") is True
def test_string_eq(self):
assert _safe_eval('"hello" == "hello"') is True
def test_string_neq(self):
assert _safe_eval('"a" != "b"') is True
def test_chained_comparison(self):
assert _safe_eval("1 < 2 < 3") is True
def test_chained_comparison_false(self):
assert _safe_eval("1 < 2 > 3") is False
def test_is_none(self):
assert _safe_eval("None is None") is True
def test_is_not_none(self):
assert _safe_eval("1 is not None") is True
class TestSafeEvalIn:
"""Test 'in' / 'not in' operators."""
def test_in_list(self):
assert _safe_eval('"abc" in ["abc", "def"]') is True
def test_not_in_list(self):
assert _safe_eval('"x" not in ["a", "b"]') is True
def test_int_in_list(self):
assert _safe_eval("2 in [1, 2, 3]") is True
def test_in_string(self):
assert _safe_eval('"lo" in "hello"') is True
class TestSafeEvalBooleanLogic:
"""Test and / or / not operators."""
def test_and_true(self):
assert _safe_eval("True and True") is True
def test_and_false(self):
assert _safe_eval("True and False") is False
def test_or_true(self):
assert _safe_eval("False or True") is True
def test_or_false(self):
assert _safe_eval("False or False") is False
def test_not_true(self):
assert _safe_eval("not False") is True
def test_not_false(self):
assert _safe_eval("not True") is False
def test_complex_boolean(self):
assert _safe_eval("(1 == 1) and (2 > 1) or False") is True
class TestSafeEvalArithmetic:
"""Test arithmetic operators."""
def test_add(self):
assert _safe_eval("1 + 2") == 3
def test_sub(self):
assert _safe_eval("5 - 3") == 2
def test_mul(self):
assert _safe_eval("3 * 4") == 12
def test_div(self):
assert _safe_eval("10 / 3") == pytest.approx(3.333, abs=0.01)
def test_floor_div(self):
assert _safe_eval("10 // 3") == 3
def test_mod(self):
assert _safe_eval("10 % 3") == 1
def test_combined_arithmetic_comparison(self):
assert _safe_eval("1 + 2 == 3") is True
class TestSafeEvalVariables:
"""Test variable binding (the feature that justified the unification)."""
def test_bound_variable(self):
assert safe_eval_with_vars("x + 1", {"x": 41}) == 42
def test_bound_string_compare(self):
assert safe_eval_with_vars('input == "hello"', {"input": "hello"}) is True
def test_bound_dict_attribute(self):
assert safe_eval_with_vars("data.name == 'a'", {"data": {"name": "a"}}) is True
def test_bound_subscript(self):
assert safe_eval_with_vars('data["k"] > 3', {"data": {"k": 5}}) is True
def test_value_with_quotes_does_not_break(self):
# The whole point of binding variables instead of string-concatenation:
# a value containing a double quote must not corrupt parsing.
assert safe_eval_with_vars('v == val', {"v": 'a"b', "val": 'a"b'}) is True
def test_unbound_variable_raises(self):
with pytest.raises(ValueError):
safe_eval_with_vars("x + 1", {})
class TestSafeEvalSecurity:
"""Ensure dangerous constructs are rejected.
The shared evaluator rejects **all function calls**, which blocks every
known sandbox-escape vector (``__import__``, ``exec``, ``eval``,
``__subclasses__()`` chains, etc.). Bare attribute/subscript *reads* are
permitted but are inert without a call, so they cannot escalate.
"""
def test_import_blocked(self):
with pytest.raises((ValueError, SyntaxError)):
_safe_eval('__import__("os")')
def test_function_call_blocked(self):
with pytest.raises(ValueError):
_safe_eval('print("hello")')
def test_open_blocked(self):
with pytest.raises(ValueError):
_safe_eval('open("/etc/passwd")')
def test_class_subclasses_blocked(self):
with pytest.raises((ValueError, SyntaxError)):
_safe_eval('().__class__.__subclasses__()')
def test_exec_blocked(self):
with pytest.raises(ValueError):
_safe_eval('exec("import os")')
def test_eval_blocked(self):
with pytest.raises(ValueError):
_safe_eval('eval("1+1")')
def test_lambda_blocked(self):
with pytest.raises((ValueError, SyntaxError)):
_safe_eval('lambda: 1')
def test_any_call_blocked(self):
# Even a call on an otherwise-safe attribute read must be rejected.
with pytest.raises(ValueError):
_safe_eval('"hello".upper()')
def test_unknown_variable_reference_blocked(self):
with pytest.raises(ValueError):
_safe_eval('x + 1')