artifacts: add calculators/ — the 30 built calculators (5/variant) + machine-docs + git logs
This commit is contained in:
@@ -0,0 +1,43 @@
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"""Evaluator for the calc AST.
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Result type rule: if the result is a whole number, return int; otherwise return float.
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Division is always true division. Division by zero raises EvalError.
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"""
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from calc.parser import Num, BinOp, Unary
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class EvalError(Exception):
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pass
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def evaluate(node) -> int | float:
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if isinstance(node, Num):
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return node.value
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if isinstance(node, Unary):
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val = evaluate(node.operand)
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if node.op == '-':
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return _coerce(-val)
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raise EvalError(f"Unknown unary op: {node.op!r}")
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if isinstance(node, BinOp):
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left = evaluate(node.left)
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right = evaluate(node.right)
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if node.op == '+':
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return _coerce(left + right)
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if node.op == '-':
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return _coerce(left - right)
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if node.op == '*':
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return _coerce(left * right)
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if node.op == '/':
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if right == 0:
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raise EvalError("Division by zero")
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return _coerce(left / right)
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raise EvalError(f"Unknown binary op: {node.op!r}")
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raise EvalError(f"Unknown node type: {type(node)!r}")
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def _coerce(val: int | float) -> int | float:
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"""Return int if val is whole-valued, otherwise float."""
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if isinstance(val, float) and val.is_integer():
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return int(val)
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return val
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@@ -0,0 +1,62 @@
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"""Lexer for arithmetic expressions."""
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from dataclasses import dataclass
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from typing import Union
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class LexError(Exception):
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pass
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@dataclass
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class Token:
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kind: str
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value: Union[int, float, None]
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def __repr__(self):
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return f"{self.kind}({self.value!r})"
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def tokenize(src: str) -> list:
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tokens = []
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i = 0
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while i < len(src):
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ch = src[i]
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if ch in ' \t':
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i += 1
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continue
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if ch.isdigit() or (ch == '.' and i + 1 < len(src) and src[i + 1].isdigit()):
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j = i
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while j < len(src) and src[j].isdigit():
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j += 1
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if j < len(src) and src[j] == '.':
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j += 1
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while j < len(src) and src[j].isdigit():
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j += 1
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tokens.append(Token('NUMBER', float(src[i:j])))
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else:
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tokens.append(Token('NUMBER', int(src[i:j])))
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i = j
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continue
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if ch == '+':
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tokens.append(Token('PLUS', None))
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elif ch == '-':
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tokens.append(Token('MINUS', None))
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elif ch == '*':
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tokens.append(Token('STAR', None))
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elif ch == '/':
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tokens.append(Token('SLASH', None))
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elif ch == '(':
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tokens.append(Token('LPAREN', None))
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elif ch == ')':
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tokens.append(Token('RPAREN', None))
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else:
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raise LexError(f"Invalid character {ch!r} at position {i}")
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i += 1
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tokens.append(Token('EOF', None))
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return tokens
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@@ -0,0 +1,113 @@
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"""Recursive-descent parser for arithmetic expressions.
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AST node shapes:
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Num(value) — numeric literal; value is int or float
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BinOp(op, left, right) — binary op; op in {'+', '-', '*', '/'}
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Unary(op, operand) — unary op; op is '-'
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Grammar (lowest to highest precedence):
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expr → term (('+' | '-') term)*
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term → unary (('*' | '/') unary)*
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unary → '-' unary | primary
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primary → NUMBER | '(' expr ')'
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"""
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from dataclasses import dataclass
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from typing import Union
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class ParseError(Exception):
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pass
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@dataclass
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class Num:
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value: Union[int, float]
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def __repr__(self):
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return f"Num({self.value!r})"
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@dataclass
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class BinOp:
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op: str
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left: object
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right: object
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def __repr__(self):
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return f"BinOp({self.op!r}, {self.left!r}, {self.right!r})"
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@dataclass
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class Unary:
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op: str
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operand: object
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def __repr__(self):
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return f"Unary({self.op!r}, {self.operand!r})"
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Node = Union[Num, BinOp, Unary]
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def parse(tokens: list) -> Node:
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"""Parse a token list produced by tokenize() and return the AST root."""
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if not tokens:
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raise ParseError("Empty token list")
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p = _Parser(tokens)
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tree = p.expr()
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if p.current().kind != 'EOF':
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raise ParseError(f"Unexpected token {p.current()!r} after expression")
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return tree
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class _Parser:
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def __init__(self, tokens):
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self._tokens = tokens
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self._pos = 0
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def current(self):
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return self._tokens[self._pos]
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def consume(self, kind=None):
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tok = self.current()
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if kind is not None and tok.kind != kind:
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raise ParseError(f"Expected {kind!r}, got {tok!r}")
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self._pos += 1
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return tok
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def expr(self):
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left = self.term()
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while self.current().kind in ('PLUS', 'MINUS'):
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tok = self.consume()
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op = '+' if tok.kind == 'PLUS' else '-'
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right = self.term()
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left = BinOp(op, left, right)
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return left
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def term(self):
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left = self.unary()
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while self.current().kind in ('STAR', 'SLASH'):
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tok = self.consume()
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op = '*' if tok.kind == 'STAR' else '/'
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right = self.unary()
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left = BinOp(op, left, right)
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return left
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def unary(self):
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if self.current().kind == 'MINUS':
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self.consume()
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return Unary('-', self.unary())
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return self.primary()
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def primary(self):
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tok = self.current()
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if tok.kind == 'NUMBER':
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self.consume()
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return Num(tok.value)
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if tok.kind == 'LPAREN':
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self.consume()
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node = self.expr()
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self.consume('RPAREN')
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return node
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raise ParseError(f"Unexpected token {tok!r}")
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@@ -0,0 +1,98 @@
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"""Tests for calc/evaluator.py covering D1-D4."""
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import subprocess
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import sys
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import unittest
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from calc.lexer import tokenize
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from calc.parser import parse
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from calc.evaluator import EvalError, evaluate
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def calc(s):
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return evaluate(parse(tokenize(s)))
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class TestArithmetic(unittest.TestCase):
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def test_precedence(self):
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self.assertEqual(calc("2+3*4"), 14)
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def test_parens(self):
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self.assertEqual(calc("(2+3)*4"), 20)
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def test_left_associative_sub(self):
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self.assertEqual(calc("8-3-2"), 3)
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def test_unary_minus(self):
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self.assertEqual(calc("-2+5"), 3)
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def test_unary_in_mul(self):
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self.assertEqual(calc("2*-3"), -6)
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class TestDivision(unittest.TestCase):
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def test_true_division(self):
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self.assertEqual(calc("7/2"), 3.5)
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def test_div_by_zero(self):
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with self.assertRaises(EvalError):
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calc("1/0")
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class TestResultType(unittest.TestCase):
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def test_whole_division_returns_int(self):
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result = calc("4/2")
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self.assertEqual(result, 2)
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self.assertIsInstance(result, int)
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def test_non_whole_returns_float(self):
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result = calc("7/2")
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self.assertIsInstance(result, float)
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def test_addition_int(self):
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self.assertIsInstance(calc("1+2"), int)
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class TestCLI(unittest.TestCase):
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def _run(self, expr):
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return subprocess.run(
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[sys.executable, "calc.py", expr],
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capture_output=True,
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text=True,
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)
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def test_cli_basic(self):
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r = self._run("2+3*4")
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self.assertEqual(r.returncode, 0)
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self.assertEqual(r.stdout.strip(), "14")
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def test_cli_parens(self):
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r = self._run("(2+3)*4")
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self.assertEqual(r.returncode, 0)
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self.assertEqual(r.stdout.strip(), "20")
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def test_cli_float(self):
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r = self._run("7/2")
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self.assertEqual(r.returncode, 0)
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self.assertEqual(r.stdout.strip(), "3.5")
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def test_cli_whole_float(self):
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r = self._run("4/2")
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self.assertEqual(r.returncode, 0)
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self.assertEqual(r.stdout.strip(), "2")
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def test_cli_div_zero_error(self):
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r = self._run("1/0")
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self.assertNotEqual(r.returncode, 0)
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self.assertTrue(r.stderr.strip())
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self.assertNotIn("Traceback", r.stderr)
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def test_cli_invalid_expr_error(self):
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r = self._run("1 +")
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self.assertNotEqual(r.returncode, 0)
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self.assertTrue(r.stderr.strip())
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self.assertNotIn("Traceback", r.stderr)
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if __name__ == "__main__":
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unittest.main()
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@@ -0,0 +1,88 @@
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import unittest
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from calc.lexer import tokenize, Token, LexError
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def kinds(src):
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return [t.kind for t in tokenize(src)]
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def tok(src):
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return [(t.kind, t.value) for t in tokenize(src)]
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class TestNumbers(unittest.TestCase):
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def test_integer(self):
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result = tokenize("42")
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self.assertEqual(result[0], Token('NUMBER', 42))
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self.assertEqual(result[1].kind, 'EOF')
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self.assertIsInstance(result[0].value, int)
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def test_float_standard(self):
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result = tokenize("3.14")
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self.assertAlmostEqual(result[0].value, 3.14)
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self.assertEqual(result[0].kind, 'NUMBER')
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def test_float_leading_dot(self):
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result = tokenize(".5")
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self.assertAlmostEqual(result[0].value, 0.5)
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def test_float_trailing_dot(self):
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result = tokenize("10.")
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self.assertAlmostEqual(result[0].value, 10.0)
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self.assertIsInstance(result[0].value, float)
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class TestOperatorsAndParens(unittest.TestCase):
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def test_operators(self):
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self.assertEqual(kinds("1+2*3"), ['NUMBER', 'PLUS', 'NUMBER', 'STAR', 'NUMBER', 'EOF'])
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def test_minus_slash(self):
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ks = kinds("4-2/1")
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self.assertIn('MINUS', ks)
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self.assertIn('SLASH', ks)
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def test_parens(self):
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ks = kinds("(1)")
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self.assertIn('LPAREN', ks)
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self.assertIn('RPAREN', ks)
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def test_complex_expr(self):
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result = tok("3.5*(1-2)")
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expected_kinds = ['NUMBER', 'STAR', 'LPAREN', 'NUMBER', 'MINUS', 'NUMBER', 'RPAREN', 'EOF']
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self.assertEqual([k for k, v in result], expected_kinds)
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self.assertAlmostEqual(result[0][1], 3.5)
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class TestWhitespaceAndErrors(unittest.TestCase):
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def test_whitespace_skipped(self):
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result = tok(" 12 + 3 ")
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self.assertEqual([k for k, v in result], ['NUMBER', 'PLUS', 'NUMBER', 'EOF'])
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self.assertEqual(result[0][1], 12)
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self.assertEqual(result[2][1], 3)
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def test_tab_whitespace(self):
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result = kinds("\t1\t+\t2\t")
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self.assertEqual(result, ['NUMBER', 'PLUS', 'NUMBER', 'EOF'])
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def test_at_raises_lex_error(self):
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with self.assertRaises(LexError) as ctx:
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tokenize("1 @ 2")
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self.assertIn('@', str(ctx.exception))
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def test_dollar_raises_lex_error(self):
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with self.assertRaises(LexError):
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tokenize("$10")
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def test_letter_raises_lex_error(self):
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with self.assertRaises(LexError):
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tokenize("abc")
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def test_error_reports_position(self):
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with self.assertRaises(LexError) as ctx:
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tokenize("1 @ 2")
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msg = str(ctx.exception)
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self.assertIn('2', msg)
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if __name__ == '__main__':
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unittest.main()
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@@ -0,0 +1,93 @@
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import unittest
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from calc.lexer import tokenize
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from calc.parser import parse, ParseError, Num, BinOp, Unary
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def p(src):
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return parse(tokenize(src))
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class TestPrecedence(unittest.TestCase):
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"""D1 — * and / bind tighter than + and -."""
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def test_mul_over_add(self):
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self.assertEqual(p('1+2*3'), BinOp('+', Num(1), BinOp('*', Num(2), Num(3))))
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def test_mul_over_sub(self):
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self.assertEqual(p('1-2*3'), BinOp('-', Num(1), BinOp('*', Num(2), Num(3))))
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def test_div_over_add(self):
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self.assertEqual(p('4+6/2'), BinOp('+', Num(4), BinOp('/', Num(6), Num(2))))
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class TestLeftAssociativity(unittest.TestCase):
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"""D2 — same-precedence operators associate left."""
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def test_sub_left(self):
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self.assertEqual(p('8-3-2'), BinOp('-', BinOp('-', Num(8), Num(3)), Num(2)))
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def test_div_left(self):
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self.assertEqual(p('8/4/2'), BinOp('/', BinOp('/', Num(8), Num(4)), Num(2)))
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def test_add_left(self):
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self.assertEqual(p('1+2+3'), BinOp('+', BinOp('+', Num(1), Num(2)), Num(3)))
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def test_mul_left(self):
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self.assertEqual(p('2*3*4'), BinOp('*', BinOp('*', Num(2), Num(3)), Num(4)))
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class TestParentheses(unittest.TestCase):
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"""D3 — parens override precedence."""
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def test_paren_overrides_precedence(self):
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self.assertEqual(p('(1+2)*3'), BinOp('*', BinOp('+', Num(1), Num(2)), Num(3)))
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def test_nested_parens(self):
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self.assertEqual(p('((2+3))*4'), BinOp('*', BinOp('+', Num(2), Num(3)), Num(4)))
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def test_paren_right_side(self):
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self.assertEqual(p('3*(1+2)'), BinOp('*', Num(3), BinOp('+', Num(1), Num(2))))
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class TestUnaryMinus(unittest.TestCase):
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"""D4 — leading and nested unary minus."""
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def test_unary_literal(self):
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self.assertEqual(p('-5'), Unary('-', Num(5)))
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def test_unary_paren(self):
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self.assertEqual(p('-(1+2)'), Unary('-', BinOp('+', Num(1), Num(2))))
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def test_unary_in_mul(self):
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self.assertEqual(p('3 * -2'), BinOp('*', Num(3), Unary('-', Num(2))))
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def test_double_unary(self):
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self.assertEqual(p('--5'), Unary('-', Unary('-', Num(5))))
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class TestErrors(unittest.TestCase):
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"""D5 — malformed input raises ParseError."""
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def test_trailing_op(self):
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with self.assertRaises(ParseError):
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p('1 +')
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def test_unclosed_paren(self):
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with self.assertRaises(ParseError):
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p('(1')
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def test_consecutive_numbers(self):
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with self.assertRaises(ParseError):
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p('1 2')
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def test_close_before_open(self):
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with self.assertRaises(ParseError):
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p(')(')
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def test_empty(self):
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with self.assertRaises(ParseError):
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p('')
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if __name__ == '__main__':
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unittest.main()
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