test/test_calculator.py

"""
Tests for calculator tool (safe mathematical evaluation)
Author: @mangubee
Date: 2026-01-02

Tests cover:
- Basic arithmetic operations
- Mathematical functions
- Safety checks (no code execution, no imports, etc.)
- Timeout protection
- Complexity limits
- Error handling
"""

import pytest
from src.tools.calculator import safe_eval


# ============================================================================
# Basic Arithmetic Tests
# ============================================================================

def test_addition():
    """Test basic addition"""
    result = safe_eval("2 + 3")
    assert result["result"] == 5
    assert result["success"] is True


def test_subtraction():
    """Test basic subtraction"""
    result = safe_eval("10 - 4")
    assert result["result"] == 6


def test_multiplication():
    """Test basic multiplication"""
    result = safe_eval("6 * 7")
    assert result["result"] == 42


def test_division():
    """Test basic division"""
    result = safe_eval("15 / 3")
    assert result["result"] == 5.0


def test_floor_division():
    """Test floor division"""
    result = safe_eval("17 // 5")
    assert result["result"] == 3


def test_modulo():
    """Test modulo operation"""
    result = safe_eval("17 % 5")
    assert result["result"] == 2


def test_exponentiation():
    """Test exponentiation"""
    result = safe_eval("2 ** 8")
    assert result["result"] == 256


def test_negative_numbers():
    """Test negative numbers"""
    result = safe_eval("-5 + 3")
    assert result["result"] == -2


def test_complex_expression():
    """Test complex arithmetic expression"""
    result = safe_eval("(2 + 3) * 4 - 10 / 2")
    assert result["result"] == 15.0


# ============================================================================
# Mathematical Function Tests
# ============================================================================

def test_sqrt():
    """Test square root function"""
    result = safe_eval("sqrt(16)")
    assert result["result"] == 4.0


def test_abs():
    """Test absolute value"""
    result = safe_eval("abs(-42)")
    assert result["result"] == 42


def test_round():
    """Test rounding"""
    result = safe_eval("round(3.7)")
    assert result["result"] == 4


def test_min():
    """Test min function"""
    result = safe_eval("min(5, 2, 8, 1)")
    assert result["result"] == 1


def test_max():
    """Test max function"""
    result = safe_eval("max(5, 2, 8, 1)")
    assert result["result"] == 8


def test_trigonometric():
    """Test trigonometric functions"""
    result = safe_eval("sin(0)")
    assert result["result"] == 0.0

    result = safe_eval("cos(0)")
    assert result["result"] == 1.0


def test_logarithm():
    """Test logarithmic functions"""
    result = safe_eval("log10(100)")
    assert result["result"] == 2.0


def test_constants():
    """Test mathematical constants"""
    result = safe_eval("pi")
    assert abs(result["result"] - 3.14159) < 0.001

    result = safe_eval("e")
    assert abs(result["result"] - 2.71828) < 0.001


def test_factorial():
    """Test factorial function"""
    result = safe_eval("factorial(5)")
    assert result["result"] == 120


def test_nested_functions():
    """Test nested function calls"""
    result = safe_eval("sqrt(abs(-16))")
    assert result["result"] == 4.0


# ============================================================================
# Security Tests
# ============================================================================

def test_no_import():
    """Test that imports are blocked"""
    with pytest.raises(SyntaxError):
        safe_eval("import os")


def test_no_exec():
    """Test that exec is blocked"""
    with pytest.raises((ValueError, SyntaxError)):
        safe_eval("exec('print(1)')")


def test_no_eval():
    """Test that eval is blocked"""
    with pytest.raises((ValueError, SyntaxError)):
        safe_eval("eval('1+1')")


def test_no_lambda():
    """Test that lambda is blocked"""
    with pytest.raises((ValueError, SyntaxError)):
        safe_eval("lambda x: x + 1")


def test_no_attribute_access():
    """Test that attribute access is blocked"""
    with pytest.raises(ValueError):
        safe_eval("(1).__class__")


def test_no_list_comprehension():
    """Test that list comprehensions are blocked"""
    with pytest.raises(ValueError):
        safe_eval("[x for x in range(10)]")


def test_no_dict_access():
    """Test that dict operations are blocked"""
    with pytest.raises((ValueError, SyntaxError)):
        safe_eval("{'a': 1}")


def test_no_undefined_names():
    """Test that undefined variable names are blocked"""
    with pytest.raises(ValueError, match="Undefined name"):
        safe_eval("undefined_variable + 1")


def test_no_dangerous_functions():
    """Test that dangerous functions are blocked"""
    with pytest.raises(ValueError, match="Unsupported function"):
        safe_eval("open('file.txt')")


# ============================================================================
# Error Handling Tests
# ============================================================================

def test_division_by_zero():
    """Test division by zero raises error"""
    with pytest.raises(ZeroDivisionError):
        safe_eval("10 / 0")


def test_invalid_syntax():
    """Test invalid syntax raises error"""
    with pytest.raises(SyntaxError):
        safe_eval("2 +* 3")


def test_empty_expression():
    """Test empty expression returns graceful error dict"""
    result = safe_eval("")
    assert result["success"] is False
    assert "Empty expression" in result["error"]
    assert result["result"] is None


def test_too_long_expression():
    """Test expression length limit returns graceful error dict"""
    long_expr = "1 + " * 300 + "1"
    result = safe_eval(long_expr)
    assert result["success"] is False
    assert "too long" in result["error"]
    assert result["result"] is None


def test_huge_exponent():
    """Test that huge exponents are blocked"""
    with pytest.raises(ValueError, match="Exponent too large"):
        safe_eval("2 ** 10000")


def test_sqrt_negative():
    """Test sqrt of negative number raises error"""
    with pytest.raises(ValueError):
        safe_eval("sqrt(-1)")


def test_factorial_negative():
    """Test factorial of negative number raises error"""
    with pytest.raises(ValueError):
        safe_eval("factorial(-5)")


# ============================================================================
# Edge Case Tests
# ============================================================================

def test_whitespace_handling():
    """Test that whitespace is handled correctly"""
    result = safe_eval("  2 + 3  ")
    assert result["result"] == 5


def test_floating_point():
    """Test floating point arithmetic"""
    result = safe_eval("3.14 * 2")
    assert abs(result["result"] - 6.28) < 0.01


def test_very_small_numbers():
    """Test very small numbers"""
    result = safe_eval("0.0001 + 0.0002")
    assert abs(result["result"] - 0.0003) < 0.00001


def test_scientific_notation():
    """Test scientific notation"""
    result = safe_eval("1e3 + 2e2")
    assert result["result"] == 1200.0


def test_parentheses_precedence():
    """Test that parentheses affect precedence correctly"""
    result1 = safe_eval("2 + 3 * 4")
    assert result1["result"] == 14

    result2 = safe_eval("(2 + 3) * 4")
    assert result2["result"] == 20


def test_multiple_operations():
    """Test chaining multiple operations"""
    result = safe_eval("10 + 20 - 5 * 2 / 2 + 3")
    assert result["result"] == 28.0