Join the 1-day Testing & QA Summit featuring 15+ Expert Speakers.Register for FREE! Join TestMu Conference

How to use is_len_call method in refurb

Best Python code snippet using refurb_python

subscripts.py

Source:subscripts.py

1import ast2from typing_extensions import final3from wemake_python_styleguide.logic import source4from wemake_python_styleguide.logic.tree import functions, operators, slices5from wemake_python_styleguide.violations import (6    best_practices,7    consistency,8    refactoring,9)10from wemake_python_styleguide.visitors import base11@final12class SubscriptVisitor(base.BaseNodeVisitor):13    """Checks subscripts used in the code."""14    def visit_Subscript(self, node: ast.Subscript) -> None:15        """16        Visits subscript.17        Raises:18            RedundantSubscriptViolation19        """20        self._check_redundant_subscript(node)21        self.generic_visit(node)22    def _check_redundant_subscript(self, node: ast.Subscript) -> None:23        if not isinstance(node.slice, ast.Slice):24            return25        lower_ok = (26            node.slice.lower is None or (27                not self._is_zero(node.slice.lower) and28                not self._is_none(node.slice.lower)29            )30        )31        upper_ok = (32            node.slice.upper is None or33            not self._is_none(node.slice.upper)34        )35        step_ok = (36            node.slice.step is None or (37                not self._is_one(node.slice.step) and38                not self._is_none(node.slice.step)39            )40        )41        if not (lower_ok and upper_ok and step_ok):42            self.add_violation(43                consistency.RedundantSubscriptViolation(44                    node, text=str(node),45                ),46            )47    def _is_none(self, component_value: ast.expr) -> bool:48        return (49            isinstance(component_value, ast.NameConstant) and50            component_value.value is None51        )52    def _is_zero(self, component_value: ast.expr) -> bool:53        return isinstance(component_value, ast.Num) and component_value.n == 054    def _is_one(self, component_value: ast.expr) -> bool:55        return isinstance(component_value, ast.Num) and component_value.n == 156@final57class ImplicitDictGetVisitor(base.BaseNodeVisitor):58    """Checks for correct ``.get`` usage in code."""59    def visit_If(self, node: ast.If) -> None:60        """61        Checks the compares.62        Raises:63            ImplicitDictGetViolation64        """65        self._check_implicit_get(node)66        self.generic_visit(node)67    def _check_implicit_get(self, node: ast.If) -> None:68        if not isinstance(node.test, ast.Compare):69            return70        if not isinstance(node.test.ops[0], ast.In):71            return72        checked_key = source.node_to_string(node.test.left)73        checked_collection = source.node_to_string(node.test.comparators[0])74        for sub in ast.walk(node):75            if not isinstance(sub, ast.Subscript):76                continue77            if slices.is_same_slice(checked_collection, checked_key, sub):78                self.add_violation(refactoring.ImplicitDictGetViolation(sub))79@final80class CorrectKeyVisitor(base.BaseNodeVisitor):81    """Checks for correct keys usage in your code."""82    def visit_Subscript(self, node: ast.Subscript) -> None:83        """84        Checks that key usage is correct, without any errors.85        Raises:86            FloatKeyViolation87            ImplicitNegativeIndexViolation88        """89        self._check_float_key(node)90        self._check_len_call(node)91        self.generic_visit(node)92    def _check_float_key(self, node: ast.Subscript) -> None:93        is_float_key = (94            isinstance(node.slice, ast.Index) and95            self._is_float_key(node.slice)96        )97        if is_float_key:98            self.add_violation(best_practices.FloatKeyViolation(node))99    def _check_len_call(self, node: ast.Subscript) -> None:100        is_len_call = (101            isinstance(node.slice, ast.Index) and102            isinstance(node.slice.value, ast.BinOp) and103            isinstance(node.slice.value.op, ast.Sub) and104            self._is_wrong_len(105                node.slice.value,106                source.node_to_string(node.value),107            )108        )109        if is_len_call:110            self.add_violation(111                refactoring.ImplicitNegativeIndexViolation(node),112            )113    def _is_wrong_len(self, node: ast.BinOp, element: str) -> bool:114        return (115            isinstance(node.left, ast.Call) and116            bool(functions.given_function_called(node.left, {'len'})) and117            source.node_to_string(node.left.args[0]) == element118        )119    def _is_float_key(self, node: ast.Index) -> bool:120        real_node = operators.unwrap_unary_node(node.value)121        return (122            isinstance(real_node, ast.Num) and123            isinstance(real_node.n, float)...

no_len_cmp.py

Source:no_len_cmp.py

...70            return True71        case DictExpr() | ListExpr() | StrExpr() | TupleExpr():72            return True73    return False74def is_len_call(node: CallExpr) -> bool:75    match node:76        case CallExpr(77            callee=NameExpr(fullname="builtins.len"),78            args=[arg],79        ) if is_builtin_container_like(arg):80            return True81    return False82IS_COMPARISON_TRUTHY: dict[tuple[str, int], bool] = {83    ("==", 0): False,84    ("<=", 0): False,85    (">", 0): True,86    ("!=", 0): True,87    (">=", 1): True,88}89class LenComparisonVisitor(TraverserVisitor):90    errors: list[Error]91    def __init__(self, errors: list[Error]) -> None:92        super().__init__()93        self.errors = errors94        for name, ty in METHOD_NODE_MAPPINGS.items():95            if ty in (ComparisonExpr, UnaryExpr, OpExpr, CallExpr):96                continue97            def inner(self: "LenComparisonVisitor", o: Node) -> None:98                return99            setattr(self, name, inner.__get__(self))100    def visit_comparison_expr(self, node: ComparisonExpr) -> None:101        match node:102            case ComparisonExpr(103                operators=[oper],104                operands=[CallExpr() as call, IntExpr(value=num)],105            ) if is_len_call(call):106                is_truthy = IS_COMPARISON_TRUTHY.get((oper, num))107                if is_truthy is None:108                    return109                expr = "x" if is_truthy else "not x"110                self.errors.append(111                    ErrorInfo(112                        node.line,113                        node.column,114                        f"Replace `len(x) {oper} {num}` with `{expr}`",115                    )116                )117    def visit_call_expr(self, node: CallExpr) -> None:118        if is_len_call(node):119            self.errors.append(120                ErrorInfo(node.line, node.column, "Replace `len(x)` with `x`")121            )122ConditionLikeNode = (123    IfStmt124    | MatchStmt125    | GeneratorExpr126    | DictionaryComprehension127    | ConditionalExpr128    | WhileStmt129    | AssertStmt130)131def check(node: ConditionLikeNode, errors: list[Error]) -> None:132    check_condition_like(LenComparisonVisitor(errors), node)...

Automation Testing Tutorials

Learn to execute automation testing from scratch with LambdaTest Learning Hub. Right from setting up the prerequisites to run your first automation test, to following best practices and diving deeper into advanced test scenarios. LambdaTest Learning Hubs compile a list of step-by-step guides to help you be proficient with different test automation frameworks i.e. Selenium, Cypress, TestNG etc.