155 lines
4.4 KiB
Python
155 lines
4.4 KiB
Python
"""Tests for calc/parser.py — covers D1–D5."""
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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):
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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_add_mul(self):
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# 1+2*3 → BinOp('+', Num(1), BinOp('*', Num(2), Num(3)))
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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_add(self):
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# 2*3+4 → BinOp('+', BinOp('*', Num(2), Num(3)), Num(4))
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self.assertEqual(p("2*3+4"), BinOp("+", BinOp("*", Num(2), Num(3)), Num(4)))
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def test_add_div(self):
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# 1+8/4 → BinOp('+', Num(1), BinOp('/', Num(8), Num(4)))
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self.assertEqual(p("1+8/4"), BinOp("+", Num(1), BinOp("/", Num(8), Num(4))))
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def test_sub_mul(self):
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# 10-2*3 → BinOp('-', Num(10), BinOp('*', Num(2), Num(3)))
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self.assertEqual(
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p("10-2*3"), BinOp("-", Num(10), BinOp("*", Num(2), Num(3)))
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)
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def test_single_number(self):
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self.assertEqual(p("42"), Num(42))
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def test_single_float(self):
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self.assertEqual(p("3.14"), Num(3.14))
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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_sub(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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p("8-3-2"), BinOp("-", BinOp("-", Num(8), Num(3)), Num(2))
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)
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def test_div_div(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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p("8/4/2"), BinOp("/", BinOp("/", Num(8), Num(4)), Num(2))
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)
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def test_add_add(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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p("1+2+3"), BinOp("+", BinOp("+", Num(1), Num(2)), Num(3))
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)
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def test_mul_mul(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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p("2*3*4"), 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 — parentheses override precedence."""
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def test_parens_override_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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p("(1+2)*3"), BinOp("*", BinOp("+", Num(1), Num(2)), Num(3))
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)
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def test_nested_parens(self):
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# ((1+2)) → BinOp('+', Num(1), Num(2))
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self.assertEqual(p("((1+2))"), BinOp("+", Num(1), Num(2)))
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def test_parens_inside_add(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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p("1+(2+3)"), BinOp("+", Num(1), BinOp("+", Num(2), Num(3)))
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)
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def test_parens_alone(self):
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self.assertEqual(p("(5)"), Num(5))
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class TestUnaryMinus(unittest.TestCase):
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"""D4 — unary minus."""
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def test_leading_unary(self):
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# -5 → Unary('-', Num(5))
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self.assertEqual(p("-5"), 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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self.assertEqual(
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p("-(1+2)"), Unary("-", BinOp("+", Num(1), Num(2)))
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)
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def test_mul_unary(self):
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# 3 * -2 → BinOp('*', Num(3), Unary('-', Num(2)))
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self.assertEqual(
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p("3 * -2"), 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(p("--5"), 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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self.assertEqual(
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p("1 + -2"), 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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p(src)
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def test_trailing_op(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_before_open(self):
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self._raises(")(")
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def test_empty(self):
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self._raises("")
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def test_just_op(self):
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self._raises("*")
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def test_mismatched_parens(self):
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self._raises("(1+2")
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def test_extra_close(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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