139 lines
4.3 KiB
Python
139 lines
4.3 KiB
Python
"""Tests for calc.parser — covers D1-D5 of the parse phase."""
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import unittest
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from calc.lexer import tokenize
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from calc.parser import BinOp, Num, ParseError, Unary, parse
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def p(src: str):
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"""Convenience: tokenize and parse in one call."""
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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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# 1+2*3 => BinOp('+', Num(1), BinOp('*', Num(2), Num(3)))
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tree = p('1+2*3')
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self.assertEqual(tree, BinOp('+', Num(1), BinOp('*', Num(2), Num(3))))
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def test_div_over_sub(self):
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# 6-4/2 => BinOp('-', Num(6), BinOp('/', Num(4), Num(2)))
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tree = p('6-4/2')
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self.assertEqual(tree, BinOp('-', Num(6), BinOp('/', Num(4), Num(2))))
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def test_mul_over_sub_left(self):
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# 1+2*3+4 => BinOp('+', BinOp('+', Num(1), BinOp('*', Num(2), Num(3))), Num(4))
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tree = p('1+2*3+4')
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expected = BinOp('+', BinOp('+', Num(1), BinOp('*', Num(2), Num(3))), Num(4))
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self.assertEqual(tree, expected)
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class TestLeftAssociativity(unittest.TestCase):
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"""D2 — same-precedence ops associate left."""
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def test_sub_left(self):
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# 8-3-2 => BinOp('-', BinOp('-', Num(8), Num(3)), Num(2))
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tree = p('8-3-2')
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self.assertEqual(tree, BinOp('-', BinOp('-', Num(8), Num(3)), Num(2)))
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def test_div_left(self):
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# 8/4/2 => BinOp('/', BinOp('/', Num(8), Num(4)), Num(2))
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tree = p('8/4/2')
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self.assertEqual(tree, BinOp('/', BinOp('/', Num(8), Num(4)), Num(2)))
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def test_add_left(self):
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# 1+2+3 => BinOp('+', BinOp('+', Num(1), Num(2)), Num(3))
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tree = p('1+2+3')
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self.assertEqual(tree, BinOp('+', BinOp('+', Num(1), Num(2)), Num(3)))
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def test_mul_left(self):
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# 2*3*4 => BinOp('*', BinOp('*', Num(2), Num(3)), Num(4))
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tree = p('2*3*4')
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self.assertEqual(tree, 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_add_over_mul(self):
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# (1+2)*3 => BinOp('*', BinOp('+', Num(1), Num(2)), Num(3))
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tree = p('(1+2)*3')
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self.assertEqual(tree, BinOp('*', BinOp('+', Num(1), Num(2)), Num(3)))
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def test_paren_nested(self):
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# ((2+3)) => BinOp is gone, we get Num-ish
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tree = p('((2+3))')
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self.assertEqual(tree, BinOp('+', Num(2), Num(3)))
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def test_paren_right_side(self):
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# 3*(1+2) => BinOp('*', Num(3), BinOp('+', Num(1), Num(2)))
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tree = p('3*(1+2)')
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self.assertEqual(tree, BinOp('*', Num(3), BinOp('+', Num(1), Num(2))))
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class TestUnaryMinus(unittest.TestCase):
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"""D4 — unary minus."""
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def test_simple_unary(self):
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tree = p('-5')
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self.assertEqual(tree, Unary('-', Num(5)))
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def test_unary_of_paren(self):
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# -(1+2) => Unary('-', BinOp('+', Num(1), Num(2)))
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tree = p('-(1+2)')
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self.assertEqual(tree, Unary('-', BinOp('+', Num(1), Num(2))))
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def test_unary_in_binop(self):
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# 3 * -2 => BinOp('*', Num(3), Unary('-', Num(2)))
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tree = p('3 * -2')
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self.assertEqual(tree, BinOp('*', Num(3), Unary('-', Num(2))))
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def test_double_unary(self):
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# --5 => Unary('-', Unary('-', Num(5)))
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tree = p('--5')
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self.assertEqual(tree, Unary('-', Unary('-', Num(5))))
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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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tree = p('1 + -2')
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self.assertEqual(tree, BinOp('+', Num(1), Unary('-', Num(2))))
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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_adjacent_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_string(self):
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with self.assertRaises(ParseError):
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p('')
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def test_just_op(self):
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with self.assertRaises(ParseError):
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p('*')
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def test_mismatched_parens(self):
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with self.assertRaises(ParseError):
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p('(1+2')
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if __name__ == '__main__':
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unittest.main()
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