149 lines
4.7 KiB
Python
149 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 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_then_mul(self):
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# 1+2*3 => BinOp('+', Num(1), BinOp('*', Num(2), Num(3)))
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result = p("1+2*3")
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self.assertEqual(result, BinOp('+', Num(1), BinOp('*', Num(2), Num(3))))
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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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result = p("2*3+1")
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self.assertEqual(result, BinOp('+', BinOp('*', Num(2), Num(3)), Num(1)))
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def test_sub_then_div(self):
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# 10-4/2 => BinOp('-', Num(10), BinOp('/', Num(4), Num(2)))
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result = p("10-4/2")
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self.assertEqual(result, BinOp('-', Num(10), BinOp('/', Num(4), Num(2))))
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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_add(self):
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self.assertEqual(p("1+2"), BinOp('+', Num(1), Num(2)))
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class TestAssociativity(unittest.TestCase):
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"""D2 — same-precedence operators associate left."""
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def test_subtraction_left(self):
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# 8-3-2 => BinOp('-', BinOp('-', Num(8), Num(3)), Num(2))
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result = p("8-3-2")
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self.assertEqual(result, BinOp('-', BinOp('-', Num(8), Num(3)), Num(2)))
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def test_division_left(self):
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# 8/4/2 => BinOp('/', BinOp('/', Num(8), Num(4)), Num(2))
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result = p("8/4/2")
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self.assertEqual(result, BinOp('/', BinOp('/', Num(8), Num(4)), Num(2)))
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def test_addition_left(self):
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# 1+2+3 => BinOp('+', BinOp('+', Num(1), Num(2)), Num(3))
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result = p("1+2+3")
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self.assertEqual(result, BinOp('+', BinOp('+', Num(1), Num(2)), Num(3)))
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def test_multiplication_left(self):
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# 2*3*4 => BinOp('*', BinOp('*', Num(2), Num(3)), Num(4))
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result = p("2*3*4")
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self.assertEqual(result, BinOp('*', BinOp('*', Num(2), Num(3)), Num(4)))
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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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result = p("(1+2)*3")
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self.assertEqual(result, BinOp('*', BinOp('+', Num(1), Num(2)), Num(3)))
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def test_parens_inside(self):
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# 3*(1+2) => BinOp('*', Num(3), BinOp('+', Num(1), Num(2)))
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result = p("3*(1+2)")
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self.assertEqual(result, BinOp('*', Num(3), BinOp('+', Num(1), Num(2))))
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def test_nested_parens(self):
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# ((4)) => Num(4)
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result = p("((4))")
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self.assertEqual(result, Num(4))
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def test_parens_in_add_chain(self):
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# 1+(2+3) => BinOp('+', Num(1), BinOp('+', Num(2), Num(3)))
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result = p("1+(2+3)")
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self.assertEqual(result, BinOp('+', Num(1), BinOp('+', Num(2), Num(3))))
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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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# -5 => Unary('-', Num(5))
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result = p("-5")
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self.assertEqual(result, Unary('-', Num(5)))
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def test_unary_paren(self):
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# -(1+2) => Unary('-', BinOp('+', Num(1), Num(2)))
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result = p("-(1+2)")
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self.assertEqual(result, Unary('-', BinOp('+', Num(1), Num(2))))
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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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result = p("3 * -2")
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self.assertEqual(result, 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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result = p("--5")
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self.assertEqual(result, 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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result = p("1 + -2")
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self.assertEqual(result, 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_plus(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_two_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(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_operator(self):
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with self.assertRaises(ParseError):
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p("*")
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def test_error_is_parse_error_not_other(self):
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for bad in ("1 +", "(1", "1 2", ")(", ""):
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with self.subTest(src=bad):
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with self.assertRaises(ParseError):
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p(bad)
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if __name__ == '__main__':
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unittest.main()
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