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author | nkozlovskiy <nmk@ydb.tech> | 2023-09-29 12:24:06 +0300 |
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committer | nkozlovskiy <nmk@ydb.tech> | 2023-09-29 12:41:34 +0300 |
commit | e0e3e1717e3d33762ce61950504f9637a6e669ed (patch) | |
tree | bca3ff6939b10ed60c3d5c12439963a1146b9711 /contrib/python/pytest/py3/_pytest/mark/expression.py | |
parent | 38f2c5852db84c7b4d83adfcb009eb61541d1ccd (diff) | |
download | ydb-e0e3e1717e3d33762ce61950504f9637a6e669ed.tar.gz |
add ydb deps
Diffstat (limited to 'contrib/python/pytest/py3/_pytest/mark/expression.py')
-rw-r--r-- | contrib/python/pytest/py3/_pytest/mark/expression.py | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/contrib/python/pytest/py3/_pytest/mark/expression.py b/contrib/python/pytest/py3/_pytest/mark/expression.py new file mode 100644 index 0000000000..9287bcee50 --- /dev/null +++ b/contrib/python/pytest/py3/_pytest/mark/expression.py @@ -0,0 +1,228 @@ +r"""Evaluate match expressions, as used by `-k` and `-m`. + +The grammar is: + +expression: expr? EOF +expr: and_expr ('or' and_expr)* +and_expr: not_expr ('and' not_expr)* +not_expr: 'not' not_expr | '(' expr ')' | ident +ident: (\w|:|\+|-|\.|\[|\]|\\|/)+ + +The semantics are: + +- Empty expression evaluates to False. +- ident evaluates to True of False according to a provided matcher function. +- or/and/not evaluate according to the usual boolean semantics. +""" +import ast +import dataclasses +import enum +import re +import sys +import types +from typing import Callable +from typing import Iterator +from typing import Mapping +from typing import NoReturn +from typing import Optional +from typing import Sequence + +if sys.version_info >= (3, 8): + astNameConstant = ast.Constant +else: + astNameConstant = ast.NameConstant + + +__all__ = [ + "Expression", + "ParseError", +] + + +class TokenType(enum.Enum): + LPAREN = "left parenthesis" + RPAREN = "right parenthesis" + OR = "or" + AND = "and" + NOT = "not" + IDENT = "identifier" + EOF = "end of input" + + +@dataclasses.dataclass(frozen=True) +class Token: + __slots__ = ("type", "value", "pos") + type: TokenType + value: str + pos: int + + +class ParseError(Exception): + """The expression contains invalid syntax. + + :param column: The column in the line where the error occurred (1-based). + :param message: A description of the error. + """ + + def __init__(self, column: int, message: str) -> None: + self.column = column + self.message = message + + def __str__(self) -> str: + return f"at column {self.column}: {self.message}" + + +class Scanner: + __slots__ = ("tokens", "current") + + def __init__(self, input: str) -> None: + self.tokens = self.lex(input) + self.current = next(self.tokens) + + def lex(self, input: str) -> Iterator[Token]: + pos = 0 + while pos < len(input): + if input[pos] in (" ", "\t"): + pos += 1 + elif input[pos] == "(": + yield Token(TokenType.LPAREN, "(", pos) + pos += 1 + elif input[pos] == ")": + yield Token(TokenType.RPAREN, ")", pos) + pos += 1 + else: + match = re.match(r"(:?\w|:|\+|-|\.|\[|\]|\\|/)+", input[pos:]) + if match: + value = match.group(0) + if value == "or": + yield Token(TokenType.OR, value, pos) + elif value == "and": + yield Token(TokenType.AND, value, pos) + elif value == "not": + yield Token(TokenType.NOT, value, pos) + else: + yield Token(TokenType.IDENT, value, pos) + pos += len(value) + else: + raise ParseError( + pos + 1, + f'unexpected character "{input[pos]}"', + ) + yield Token(TokenType.EOF, "", pos) + + def accept(self, type: TokenType, *, reject: bool = False) -> Optional[Token]: + if self.current.type is type: + token = self.current + if token.type is not TokenType.EOF: + self.current = next(self.tokens) + return token + if reject: + self.reject((type,)) + return None + + def reject(self, expected: Sequence[TokenType]) -> NoReturn: + raise ParseError( + self.current.pos + 1, + "expected {}; got {}".format( + " OR ".join(type.value for type in expected), + self.current.type.value, + ), + ) + + +# True, False and None are legal match expression identifiers, +# but illegal as Python identifiers. To fix this, this prefix +# is added to identifiers in the conversion to Python AST. +IDENT_PREFIX = "$" + + +def expression(s: Scanner) -> ast.Expression: + if s.accept(TokenType.EOF): + ret: ast.expr = astNameConstant(False) + else: + ret = expr(s) + s.accept(TokenType.EOF, reject=True) + return ast.fix_missing_locations(ast.Expression(ret)) + + +def expr(s: Scanner) -> ast.expr: + ret = and_expr(s) + while s.accept(TokenType.OR): + rhs = and_expr(s) + ret = ast.BoolOp(ast.Or(), [ret, rhs]) + return ret + + +def and_expr(s: Scanner) -> ast.expr: + ret = not_expr(s) + while s.accept(TokenType.AND): + rhs = not_expr(s) + ret = ast.BoolOp(ast.And(), [ret, rhs]) + return ret + + +def not_expr(s: Scanner) -> ast.expr: + if s.accept(TokenType.NOT): + return ast.UnaryOp(ast.Not(), not_expr(s)) + if s.accept(TokenType.LPAREN): + ret = expr(s) + s.accept(TokenType.RPAREN, reject=True) + return ret + ident = s.accept(TokenType.IDENT) + if ident: + return ast.Name(IDENT_PREFIX + ident.value, ast.Load()) + s.reject((TokenType.NOT, TokenType.LPAREN, TokenType.IDENT)) + + +class MatcherAdapter(Mapping[str, bool]): + """Adapts a matcher function to a locals mapping as required by eval().""" + + def __init__(self, matcher: Callable[[str], bool]) -> None: + self.matcher = matcher + + def __getitem__(self, key: str) -> bool: + return self.matcher(key[len(IDENT_PREFIX) :]) + + def __iter__(self) -> Iterator[str]: + raise NotImplementedError() + + def __len__(self) -> int: + raise NotImplementedError() + + +class Expression: + """A compiled match expression as used by -k and -m. + + The expression can be evaluated against different matchers. + """ + + __slots__ = ("code",) + + def __init__(self, code: types.CodeType) -> None: + self.code = code + + @classmethod + def compile(self, input: str) -> "Expression": + """Compile a match expression. + + :param input: The input expression - one line. + """ + astexpr = expression(Scanner(input)) + code: types.CodeType = compile( + astexpr, + filename="<pytest match expression>", + mode="eval", + ) + return Expression(code) + + def evaluate(self, matcher: Callable[[str], bool]) -> bool: + """Evaluate the match expression. + + :param matcher: + Given an identifier, should return whether it matches or not. + Should be prepared to handle arbitrary strings as input. + + :returns: Whether the expression matches or not. + """ + ret: bool = eval(self.code, {"__builtins__": {}}, MatcherAdapter(matcher)) + return ret |