def test_minus(self): assert parser.parse(lexer.lex('1 - 1')).eval() == 0
def test_sum(self): assert parser.parse(lexer.lex(' 1 + 1')).eval() == 2
def test_concat(self): assert parser.parse(lexer.lex('"a" + "b"')).eval() == "ab"
def test_open_param(self): assert parser.parse(lexer.lex('(1 + 2) * (4 - 1)')).eval() == 9
def test_div(self): assert parser.parse(lexer.lex('2 / 2')).eval() == 1
def test_mul(self): assert parser.parse(lexer.lex('2 * 2')).eval() == 4