160 lines
3.9 KiB
Python
160 lines
3.9 KiB
Python
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 → 1+(2*3)
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tree = p("1+2*3")
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self.assertEqual(
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tree,
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BinOp("+", Num(1), BinOp("*", Num(2), Num(3))),
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)
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def test_mul_add(self):
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# 3*2+1 → (3*2)+1
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tree = p("3*2+1")
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self.assertEqual(
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tree,
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BinOp("+", BinOp("*", Num(3), Num(2)), Num(1)),
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)
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def test_sub_div(self):
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# 10-4/2 → 10-(4/2)
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tree = p("10-4/2")
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self.assertEqual(
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tree,
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BinOp("-", Num(10), BinOp("/", Num(4), Num(2))),
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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(self):
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# 8-3-2 → (8-3)-2
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tree = p("8-3-2")
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self.assertEqual(
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tree,
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BinOp("-", BinOp("-", Num(8), Num(3)), Num(2)),
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)
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def test_div_left(self):
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# 8/4/2 → (8/4)/2
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tree = p("8/4/2")
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self.assertEqual(
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tree,
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BinOp("/", BinOp("/", Num(8), Num(4)), Num(2)),
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)
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def test_add_left(self):
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# 1+2+3 → (1+2)+3
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tree = p("1+2+3")
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self.assertEqual(
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tree,
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BinOp("+", BinOp("+", Num(1), Num(2)), Num(3)),
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)
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def test_mul_left(self):
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# 2*3*4 → (2*3)*4
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tree = p("2*3*4")
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self.assertEqual(
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tree,
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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 — parentheses override precedence"""
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def test_parens_force_add_first(self):
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# (1+2)*3 → mul at root, add under left
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tree = p("(1+2)*3")
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self.assertEqual(
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tree,
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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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# ((4)) → Num(4)
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tree = p("((4))")
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self.assertEqual(tree, Num(4))
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def test_parens_right(self):
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# 2*(3+4) → mul at root, add under right
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tree = p("2*(3+4)")
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self.assertEqual(
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tree,
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BinOp("*", Num(2), BinOp("+", Num(3), Num(4))),
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)
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class TestUnaryMinus(unittest.TestCase):
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"""D4 — leading and nested unary minus"""
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def test_simple(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_paren(self):
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# -(1+2) → Unary at root
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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_mul_unary(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(
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tree,
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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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tree = p("--5")
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self.assertEqual(tree, Unary("-", Unary("-", Num(5))))
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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_two_numbers(self):
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with self.assertRaises(ParseError):
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p("1 2")
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def test_close_open(self):
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with self.assertRaises(ParseError):
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p(")(")
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def test_empty(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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