test_parser.py

from parser import *

def ln(value):
    return LiteralNode(value)

def bn(l, op:BinaryOp, r):
    return BinaryOpNode(l, op, r)

def lparen():
    return Token('(', TokenVariant.OPEN_PAREN)

def rparen():
    return Token(')', TokenVariant.CLOSE_PAREN)

def test_literal():
    assert ln(3).eval() == 3
    assert ln(0).eval() == 0

def test_add():
    assert bn(ln(3), BinaryOp.ADD, ln(4)).eval() == 7
    assert bn(ln(3), BinaryOp.ADD, bn(ln(4), BinaryOp.SUB, ln(5))).eval() == 2

def test_parse_literal():
    tokens = tokenize('3')
    assert parse(tokens) == ln(3)

    tokens = tokenize('  3.14  ')
    assert parse(tokens) == ln(3.14)

def test_parse_addition():
    tokens = tokenize('3+4')
    assert parse(tokens) == bn(ln(3), BinaryOp.ADD, ln(4))

def test_parse_three_additions():
    tokens = tokenize('3+4+5')
    assert parse(tokens) == bn(bn(ln(3), BinaryOp.ADD, ln(4)), BinaryOp.ADD, ln(5))

def test_parse_add_and_sub():
    assert parse(tokenize('3+4-5')) == bn(bn(ln(3), BinaryOp.ADD, ln(4)), BinaryOp.SUB, ln(5))
    assert parse(tokenize('3-4+5')) == bn(bn(ln(3), BinaryOp.SUB, ln(4)), BinaryOp.ADD, ln(5))

def test_parse_literal_in_parens():
    tokens = tokenize('(3)')
    assert parse(tokens) == ln(3)

def test_parse_expr_in_parens():
    tokens = tokenize('(3+4)')
    assert parse(tokens) == bn(ln(3), BinaryOp.ADD, ln(4))
   

def test_literal_op_parens():
    tokens = tokenize('3 - (4 + 5)')
    assert parse(tokens) == bn(ln(3), BinaryOp.SUB, bn(ln(4), BinaryOp.ADD, ln(5)))
    
def test_parens_op_literal():
    tokens = tokenize('(3 - 4) + 5')
    assert parse(tokens) == bn(bn(ln(3), BinaryOp.SUB, ln(4)), BinaryOp.ADD, ln(5))

def test_parse_add_sub_mul_div():
    assert parse(tokenize('3+4/5')) == bn(ln(3), BinaryOp.ADD, bn(ln(4), BinaryOp.DIV, ln(5)))

def test_parse_add_sub_mul_div_add():
    result = parse(tokenize('3-4/5+6'))
    answer = result.eval()
    assert result == bn(bn(ln(3), BinaryOp.SUB, bn(ln(4), BinaryOp.DIV, ln(5))), BinaryOp.ADD, ln(6))