171 lines
4.7 KiB
Python
171 lines
4.7 KiB
Python
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 tree(src):
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return repr(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_add_then_mul(self):
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# 1+2*3 -> BinOp('+', Num(1), BinOp('*', Num(2), Num(3)))
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self.assertEqual(
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tree('1+2*3'),
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"BinOp('+', Num(1), BinOp('*', Num(2), Num(3)))",
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)
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def test_mul_then_add(self):
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# 2*3+1 -> BinOp('+', BinOp('*', Num(2), Num(3)), Num(1))
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self.assertEqual(
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tree('2*3+1'),
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"BinOp('+', BinOp('*', Num(2), Num(3)), Num(1))",
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)
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def test_sub_then_div(self):
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# 10-6/2 -> BinOp('-', Num(10), BinOp('/', Num(6), Num(2)))
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self.assertEqual(
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tree('10-6/2'),
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"BinOp('-', Num(10), BinOp('/', Num(6), Num(2)))",
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)
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def test_div_then_sub(self):
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# 6/2-1 -> BinOp('-', BinOp('/', Num(6), Num(2)), Num(1))
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self.assertEqual(
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tree('6/2-1'),
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"BinOp('-', BinOp('/', Num(6), Num(2)), Num(1))",
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)
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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_assoc(self):
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# 8-3-2 -> BinOp('-', BinOp('-', Num(8), Num(3)), Num(2))
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self.assertEqual(
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tree('8-3-2'),
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"BinOp('-', BinOp('-', Num(8), Num(3)), Num(2))",
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)
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def test_div_left_assoc(self):
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# 8/4/2 -> BinOp('/', BinOp('/', Num(8), Num(4)), Num(2))
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self.assertEqual(
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tree('8/4/2'),
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"BinOp('/', BinOp('/', Num(8), Num(4)), Num(2))",
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)
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def test_add_left_assoc(self):
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# 1+2+3 -> BinOp('+', BinOp('+', Num(1), Num(2)), Num(3))
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self.assertEqual(
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tree('1+2+3'),
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"BinOp('+', BinOp('+', Num(1), Num(2)), Num(3))",
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)
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def test_mul_left_assoc(self):
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# 2*3*4 -> BinOp('*', BinOp('*', Num(2), Num(3)), Num(4))
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self.assertEqual(
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tree('2*3*4'),
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"BinOp('*', BinOp('*', Num(2), Num(3)), Num(4))",
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)
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class TestParentheses(unittest.TestCase):
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"""D3 — parens override precedence."""
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def test_paren_overrides_mul(self):
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# (1+2)*3 -> BinOp('*', BinOp('+', Num(1), Num(2)), Num(3))
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self.assertEqual(
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tree('(1+2)*3'),
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"BinOp('*', BinOp('+', Num(1), Num(2)), Num(3))",
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)
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def test_paren_overrides_div(self):
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# 8/(2+2) -> BinOp('/', Num(8), BinOp('+', Num(2), Num(2)))
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self.assertEqual(
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tree('8/(2+2)'),
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"BinOp('/', Num(8), BinOp('+', Num(2), Num(2)))",
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)
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def test_nested_parens(self):
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# ((3)) -> Num(3)
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self.assertEqual(tree('((3))'), 'Num(3)')
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def test_paren_in_sub(self):
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# 10-(3+2) -> BinOp('-', Num(10), BinOp('+', Num(3), Num(2)))
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self.assertEqual(
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tree('10-(3+2)'),
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"BinOp('-', Num(10), BinOp('+', Num(3), Num(2)))",
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)
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class TestUnaryMinus(unittest.TestCase):
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"""D4 — unary minus."""
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def test_unary_simple(self):
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self.assertEqual(tree('-5'), "Unary('-', Num(5))")
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def test_unary_grouped(self):
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self.assertEqual(
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tree('-(1+2)'),
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"Unary('-', BinOp('+', Num(1), Num(2)))",
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)
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def test_unary_in_mul(self):
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# 3 * -2 -> BinOp('*', Num(3), Unary('-', Num(2)))
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self.assertEqual(
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tree('3 * -2'),
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"BinOp('*', Num(3), Unary('-', Num(2)))",
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)
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def test_double_unary(self):
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# --5 -> Unary('-', Unary('-', Num(5)))
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self.assertEqual(
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tree('--5'),
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"Unary('-', Unary('-', Num(5)))",
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)
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def test_unary_in_add(self):
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# 1 + -2 -> BinOp('+', Num(1), Unary('-', Num(2)))
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self.assertEqual(
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tree('1 + -2'),
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"BinOp('+', Num(1), Unary('-', Num(2)))",
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)
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class TestErrors(unittest.TestCase):
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"""D5 — malformed input raises ParseError."""
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def _raises(self, src):
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with self.assertRaises(ParseError):
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parse(tokenize(src))
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def test_trailing_operator(self):
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self._raises('1 +')
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def test_unclosed_paren(self):
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self._raises('(1')
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def test_two_numbers(self):
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self._raises('1 2')
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def test_close_open_paren(self):
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self._raises(')(')
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def test_empty_string(self):
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self._raises('')
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def test_just_operator(self):
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self._raises('+')
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def test_mismatched_paren(self):
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self._raises('(1+2')
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def test_extra_close_paren(self):
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self._raises('1+2)')
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if __name__ == '__main__':
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unittest.main()
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