def test_expr_with_addition(self):
lexer = Lexer('3 + 2')
parser = Parser(lexer)
result = parser.expr()
expected = BinOp(left=Num(Token('INTEGER', 3)),
op=Token('ADD', '+'),
right=Num(Token('INTEGER', 2)))
assert result == expected
def test_term_with_multiply(self):
lexer = Lexer('3 * 2')
parser = Parser(lexer)
result = parser.term()
expected = BinOp(left=Num(Token('INTEGER', 3)),
op=Token('MULTIPLY', '*'),
right=Num(Token('INTEGER', 2)))
assert result == expected
def test_term_with_division(self):
lexer = Lexer('3 / 2')
parser = Parser(lexer)
result = parser.term()
expected = BinOp(left=Num(Token('INTEGER', 3)),
op=Token('DIVIDE', '/'),
right=Num(Token('INTEGER', 2)))
assert result == expected
def test_parser(self):
lexer = Lexer('3 + 1')
parser = Parser(lexer)
result = parser.parse()
expected = BinOp(left=Num(Token('INTEGER', 3)),
op=Token('ADD', '+'),
right=Num(Token('INTEGER', 1)))
assert result == expected
def test_expr_with_subtraction(self):
lexer = Lexer('3 - 2')
parser = Parser(lexer)
result = parser.expr()
expected = BinOp(left=Num(Token('INTEGER', 3)),
op=Token('SUBTRACT', '-'),
right=Num(Token('INTEGER', 2)))
assert result == expected
def test_factor_with_parens(self):
lexer = Lexer('(3)')
parser = Parser(lexer)
result = parser.factor()
expected = Num(Token('INTEGER', 3))
assert result == expected
def test_factor_error(self):
lexer = Lexer('+')
parser = Parser(lexer)
with pytest.raises(SyntaxError) as ex:
parser.factor()
assert 'Invalid syntax' == str(ex.value)
def test_eat_error(self):
lexer = Lexer('3')
parser = Parser(lexer)
with pytest.raises(SyntaxError) as ex:
parser.eat('ADD')
assert 'Invalid syntax' == str(ex.value)
