108 lines
3.5 KiB
Python
108 lines
3.5 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 p(src):
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return parse(tokenize(src))
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class TestPrecedence(unittest.TestCase):
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def test_mul_tighter_than_add(self):
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# 1+2*3 → PLUS(1, STAR(2, 3)) NOT STAR(PLUS(1,2), 3)
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self.assertEqual(p('1+2*3'), BinOp('PLUS', Num(1), BinOp('STAR', Num(2), Num(3))))
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def test_mul_tighter_than_sub(self):
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# 2*3-1 → MINUS(STAR(2,3), 1)
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self.assertEqual(p('2*3-1'), BinOp('MINUS', BinOp('STAR', Num(2), Num(3)), Num(1)))
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def test_div_tighter_than_add(self):
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# 4/2+1 → PLUS(SLASH(4,2), 1)
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self.assertEqual(p('4/2+1'), BinOp('PLUS', BinOp('SLASH', Num(4), Num(2)), Num(1)))
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def test_div_tighter_than_sub(self):
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# 6-4/2 → MINUS(6, SLASH(4,2))
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self.assertEqual(p('6-4/2'), BinOp('MINUS', Num(6), BinOp('SLASH', Num(4), Num(2))))
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class TestLeftAssociativity(unittest.TestCase):
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def test_sub_left(self):
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# 8-3-2 → MINUS(MINUS(8,3), 2)
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self.assertEqual(p('8-3-2'), BinOp('MINUS', BinOp('MINUS', Num(8), Num(3)), Num(2)))
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def test_div_left(self):
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# 8/4/2 → SLASH(SLASH(8,4), 2)
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self.assertEqual(p('8/4/2'), BinOp('SLASH', BinOp('SLASH', Num(8), Num(4)), Num(2)))
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def test_add_left(self):
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# 1+2+3 → PLUS(PLUS(1,2), 3)
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self.assertEqual(p('1+2+3'), BinOp('PLUS', BinOp('PLUS', Num(1), Num(2)), Num(3)))
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def test_mul_left(self):
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# 2*3*4 → STAR(STAR(2,3), 4)
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self.assertEqual(p('2*3*4'), BinOp('STAR', BinOp('STAR', Num(2), Num(3)), Num(4)))
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class TestParentheses(unittest.TestCase):
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def test_paren_overrides_precedence(self):
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# (1+2)*3 → STAR(PLUS(1,2), 3) — plus is UNDER star
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self.assertEqual(p('(1+2)*3'), BinOp('STAR', BinOp('PLUS', Num(1), Num(2)), Num(3)))
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def test_paren_on_right(self):
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# 3*(1+2) → STAR(3, PLUS(1,2))
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self.assertEqual(p('3*(1+2)'), BinOp('STAR', Num(3), BinOp('PLUS', Num(1), Num(2))))
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def test_nested_parens(self):
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# ((2+3)) → PLUS(2,3)
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self.assertEqual(p('((2+3))'), BinOp('PLUS', Num(2), Num(3)))
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def test_single_number_in_parens(self):
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self.assertEqual(p('(42)'), Num(42))
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class TestUnaryMinus(unittest.TestCase):
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def test_leading_unary(self):
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self.assertEqual(p('-5'), Unary('MINUS', Num(5)))
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def test_unary_on_paren(self):
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# -(1+2) → UNARY(-, PLUS(1,2))
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self.assertEqual(p('-(1+2)'), Unary('MINUS', BinOp('PLUS', Num(1), Num(2))))
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def test_unary_in_mul(self):
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# 3 * -2 → STAR(3, UNARY(-,2))
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self.assertEqual(p('3 * -2'), BinOp('STAR', Num(3), Unary('MINUS', Num(2))))
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def test_double_unary(self):
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# --5 → UNARY(-,UNARY(-,5))
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self.assertEqual(p('--5'), Unary('MINUS', Unary('MINUS', Num(5))))
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def test_unary_in_add(self):
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# 1 + -2 → PLUS(1, UNARY(-,2))
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self.assertEqual(p('1 + -2'), BinOp('PLUS', Num(1), Unary('MINUS', Num(2))))
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class TestErrors(unittest.TestCase):
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def test_trailing_operator(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_mismatched_parens_close_first(self):
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with self.assertRaises(ParseError):
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p(')(')
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def test_empty_string(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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