def test_parsing_a_divide_returns_a_divide_expression():
tokens = [
Token(TokenType.NUMBER, 3),
Token(TokenType.DIVIDE),
Token(TokenType.NUMBER, 4),
]
parser = Parser(tokens)
expr = parser.parse()
assert type(expr) == DivExpr
def test_parsing_an_exponentiation_return_an_exponentiation_expression():
tokens = [
Token(TokenType.NUMBER, 3),
Token(TokenType.EXP),
Token(TokenType.NUMBER, 4),
]
parser = Parser(tokens)
expr = parser.parse()
assert type(expr) == ExpExpr
def test_parsing_a_times_returns_a_times_expression():
tokens = [
Token(TokenType.NUMBER, 3),
Token(TokenType.TIMES),
Token(TokenType.NUMBER, 4),
]
parser = Parser(tokens)
expr = parser.parse()
assert type(expr) == TimesExpr
def test_parsing_a_minus_expression():
tokens = [
Token(TokenType.NUMBER, 3),
Token(TokenType.MINUS),
Token(TokenType.NUMBER, 4),
]
parser = Parser(tokens)
expr = parser.parse()
assert type(expr) == MinusExpr
def test_parsing_a_plus_returns_a_plus_expression():
tokens = [
Token(TokenType.NUMBER, 3),
Token(TokenType.PLUS),
Token(TokenType.NUMBER, 4),
]
parser = Parser(tokens)
expr = parser.parse()
assert type(expr) == PlusExpr
def test_parsing_a_variable_returns_a_variable_expression():
tokens = [Token(TokenType.VARIABLE, "x")]
parser = Parser(tokens)
expr = parser.parse()
assert type(expr) == VarExpr
def test_parsing_a_constant_returns_a_constant_expression():
tokens = [Token(TokenType.NUMBER, 3)]
parser = Parser(tokens)
expr = parser.parse()
assert type(expr) == ConstExpr
def test_parsing_parenthesis_changes_the_precedence():
tokens = [
Token(TokenType.LEFT_PAREN),
Token(TokenType.NUMBER, 3),
Token(TokenType.PLUS),
Token(TokenType.NUMBER, 4),
Token(TokenType.RIGHT_PAREN),
Token(TokenType.TIMES),
Token(TokenType.NUMBER, 5),
]
parser = Parser(tokens)
expr = parser.parse()
assert type(expr) == TimesExpr