510 lines
17 KiB
Python
510 lines
17 KiB
Python
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"""Utilities for assertion debugging."""
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import collections.abc
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import os
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import pprint
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from typing import AbstractSet
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from typing import Any
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from typing import Callable
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from typing import Iterable
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from typing import List
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from typing import Mapping
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from typing import Optional
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from typing import Sequence
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import _pytest._code
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from _pytest import outcomes
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from _pytest._io.saferepr import _pformat_dispatch
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from _pytest._io.saferepr import safeformat
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from _pytest._io.saferepr import saferepr
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from _pytest.config import Config
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# The _reprcompare attribute on the util module is used by the new assertion
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# interpretation code and assertion rewriter to detect this plugin was
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# loaded and in turn call the hooks defined here as part of the
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# DebugInterpreter.
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_reprcompare: Optional[Callable[[str, object, object], Optional[str]]] = None
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# Works similarly as _reprcompare attribute. Is populated with the hook call
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# when pytest_runtest_setup is called.
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_assertion_pass: Optional[Callable[[int, str, str], None]] = None
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# Config object which is assigned during pytest_runtest_protocol.
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_config: Optional[Config] = None
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def format_explanation(explanation: str) -> str:
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r"""Format an explanation.
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Normally all embedded newlines are escaped, however there are
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three exceptions: \n{, \n} and \n~. The first two are intended
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cover nested explanations, see function and attribute explanations
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for examples (.visit_Call(), visit_Attribute()). The last one is
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for when one explanation needs to span multiple lines, e.g. when
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displaying diffs.
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"""
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lines = _split_explanation(explanation)
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result = _format_lines(lines)
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return "\n".join(result)
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def _split_explanation(explanation: str) -> List[str]:
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r"""Return a list of individual lines in the explanation.
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This will return a list of lines split on '\n{', '\n}' and '\n~'.
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Any other newlines will be escaped and appear in the line as the
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literal '\n' characters.
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"""
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raw_lines = (explanation or "").split("\n")
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lines = [raw_lines[0]]
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for values in raw_lines[1:]:
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if values and values[0] in ["{", "}", "~", ">"]:
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lines.append(values)
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else:
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lines[-1] += "\\n" + values
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return lines
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def _format_lines(lines: Sequence[str]) -> List[str]:
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"""Format the individual lines.
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This will replace the '{', '}' and '~' characters of our mini formatting
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language with the proper 'where ...', 'and ...' and ' + ...' text, taking
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care of indentation along the way.
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Return a list of formatted lines.
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"""
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result = list(lines[:1])
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stack = [0]
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stackcnt = [0]
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for line in lines[1:]:
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if line.startswith("{"):
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if stackcnt[-1]:
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s = "and "
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else:
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s = "where "
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stack.append(len(result))
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stackcnt[-1] += 1
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stackcnt.append(0)
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result.append(" +" + " " * (len(stack) - 1) + s + line[1:])
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elif line.startswith("}"):
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stack.pop()
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stackcnt.pop()
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result[stack[-1]] += line[1:]
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else:
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assert line[0] in ["~", ">"]
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stack[-1] += 1
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indent = len(stack) if line.startswith("~") else len(stack) - 1
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result.append(" " * indent + line[1:])
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assert len(stack) == 1
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return result
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def issequence(x: Any) -> bool:
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return isinstance(x, collections.abc.Sequence) and not isinstance(x, str)
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def istext(x: Any) -> bool:
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return isinstance(x, str)
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def isdict(x: Any) -> bool:
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return isinstance(x, dict)
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def isset(x: Any) -> bool:
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return isinstance(x, (set, frozenset))
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def isnamedtuple(obj: Any) -> bool:
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return isinstance(obj, tuple) and getattr(obj, "_fields", None) is not None
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def isdatacls(obj: Any) -> bool:
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return getattr(obj, "__dataclass_fields__", None) is not None
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def isattrs(obj: Any) -> bool:
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return getattr(obj, "__attrs_attrs__", None) is not None
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def isiterable(obj: Any) -> bool:
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try:
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iter(obj)
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return not istext(obj)
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except TypeError:
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return False
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def has_default_eq(
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obj: object,
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) -> bool:
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"""Check if an instance of an object contains the default eq
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First, we check if the object's __eq__ attribute has __code__,
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if so, we check the equally of the method code filename (__code__.co_filename)
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to the default one generated by the dataclass and attr module
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for dataclasses the default co_filename is <string>, for attrs class, the __eq__ should contain "attrs eq generated"
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"""
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# inspired from https://github.com/willmcgugan/rich/blob/07d51ffc1aee6f16bd2e5a25b4e82850fb9ed778/rich/pretty.py#L68
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if hasattr(obj.__eq__, "__code__") and hasattr(obj.__eq__.__code__, "co_filename"):
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code_filename = obj.__eq__.__code__.co_filename
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if isattrs(obj):
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return "attrs generated eq" in code_filename
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return code_filename == "<string>" # data class
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return True
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def assertrepr_compare(config, op: str, left: Any, right: Any) -> Optional[List[str]]:
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"""Return specialised explanations for some operators/operands."""
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verbose = config.getoption("verbose")
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if verbose > 1:
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left_repr = safeformat(left)
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right_repr = safeformat(right)
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else:
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# XXX: "15 chars indentation" is wrong
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# ("E AssertionError: assert "); should use term width.
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maxsize = (
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80 - 15 - len(op) - 2
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) // 2 # 15 chars indentation, 1 space around op
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left_repr = saferepr(left, maxsize=maxsize)
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right_repr = saferepr(right, maxsize=maxsize)
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summary = f"{left_repr} {op} {right_repr}"
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explanation = None
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try:
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if op == "==":
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explanation = _compare_eq_any(left, right, verbose)
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elif op == "not in":
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if istext(left) and istext(right):
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explanation = _notin_text(left, right, verbose)
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except outcomes.Exit:
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raise
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except Exception:
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explanation = [
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"(pytest_assertion plugin: representation of details failed: {}.".format(
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_pytest._code.ExceptionInfo.from_current()._getreprcrash()
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),
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" Probably an object has a faulty __repr__.)",
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]
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if not explanation:
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return None
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return [summary] + explanation
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def _compare_eq_any(left: Any, right: Any, verbose: int = 0) -> List[str]:
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explanation = []
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if istext(left) and istext(right):
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explanation = _diff_text(left, right, verbose)
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else:
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from _pytest.python_api import ApproxBase
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if isinstance(left, ApproxBase) or isinstance(right, ApproxBase):
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# Although the common order should be obtained == expected, this ensures both ways
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approx_side = left if isinstance(left, ApproxBase) else right
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other_side = right if isinstance(left, ApproxBase) else left
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explanation = approx_side._repr_compare(other_side)
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elif type(left) == type(right) and (
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isdatacls(left) or isattrs(left) or isnamedtuple(left)
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):
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# Note: unlike dataclasses/attrs, namedtuples compare only the
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# field values, not the type or field names. But this branch
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# intentionally only handles the same-type case, which was often
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# used in older code bases before dataclasses/attrs were available.
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explanation = _compare_eq_cls(left, right, verbose)
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elif issequence(left) and issequence(right):
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explanation = _compare_eq_sequence(left, right, verbose)
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elif isset(left) and isset(right):
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explanation = _compare_eq_set(left, right, verbose)
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elif isdict(left) and isdict(right):
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explanation = _compare_eq_dict(left, right, verbose)
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if isiterable(left) and isiterable(right):
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expl = _compare_eq_iterable(left, right, verbose)
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explanation.extend(expl)
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return explanation
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def _diff_text(left: str, right: str, verbose: int = 0) -> List[str]:
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"""Return the explanation for the diff between text.
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Unless --verbose is used this will skip leading and trailing
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characters which are identical to keep the diff minimal.
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"""
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from difflib import ndiff
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explanation: List[str] = []
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if verbose < 1:
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i = 0 # just in case left or right has zero length
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for i in range(min(len(left), len(right))):
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if left[i] != right[i]:
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break
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if i > 42:
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i -= 10 # Provide some context
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explanation = [
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"Skipping %s identical leading characters in diff, use -v to show" % i
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]
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left = left[i:]
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right = right[i:]
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if len(left) == len(right):
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for i in range(len(left)):
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if left[-i] != right[-i]:
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break
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if i > 42:
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i -= 10 # Provide some context
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explanation += [
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"Skipping {} identical trailing "
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"characters in diff, use -v to show".format(i)
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]
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left = left[:-i]
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right = right[:-i]
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keepends = True
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if left.isspace() or right.isspace():
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left = repr(str(left))
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right = repr(str(right))
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explanation += ["Strings contain only whitespace, escaping them using repr()"]
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# "right" is the expected base against which we compare "left",
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# see https://github.com/pytest-dev/pytest/issues/3333
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explanation += [
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line.strip("\n")
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for line in ndiff(right.splitlines(keepends), left.splitlines(keepends))
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]
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return explanation
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def _surrounding_parens_on_own_lines(lines: List[str]) -> None:
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"""Move opening/closing parenthesis/bracket to own lines."""
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opening = lines[0][:1]
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if opening in ["(", "[", "{"]:
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lines[0] = " " + lines[0][1:]
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lines[:] = [opening] + lines
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closing = lines[-1][-1:]
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if closing in [")", "]", "}"]:
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lines[-1] = lines[-1][:-1] + ","
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lines[:] = lines + [closing]
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def _compare_eq_iterable(
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left: Iterable[Any], right: Iterable[Any], verbose: int = 0
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) -> List[str]:
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if verbose <= 0 and not running_on_ci():
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return ["Use -v to get more diff"]
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# dynamic import to speedup pytest
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import difflib
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left_formatting = pprint.pformat(left).splitlines()
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right_formatting = pprint.pformat(right).splitlines()
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# Re-format for different output lengths.
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lines_left = len(left_formatting)
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lines_right = len(right_formatting)
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if lines_left != lines_right:
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left_formatting = _pformat_dispatch(left).splitlines()
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right_formatting = _pformat_dispatch(right).splitlines()
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if lines_left > 1 or lines_right > 1:
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_surrounding_parens_on_own_lines(left_formatting)
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_surrounding_parens_on_own_lines(right_formatting)
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explanation = ["Full diff:"]
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# "right" is the expected base against which we compare "left",
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# see https://github.com/pytest-dev/pytest/issues/3333
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explanation.extend(
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line.rstrip() for line in difflib.ndiff(right_formatting, left_formatting)
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)
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return explanation
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def _compare_eq_sequence(
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left: Sequence[Any], right: Sequence[Any], verbose: int = 0
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) -> List[str]:
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comparing_bytes = isinstance(left, bytes) and isinstance(right, bytes)
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explanation: List[str] = []
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len_left = len(left)
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len_right = len(right)
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for i in range(min(len_left, len_right)):
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if left[i] != right[i]:
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if comparing_bytes:
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# when comparing bytes, we want to see their ascii representation
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# instead of their numeric values (#5260)
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# using a slice gives us the ascii representation:
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# >>> s = b'foo'
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# >>> s[0]
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# 102
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# >>> s[0:1]
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# b'f'
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left_value = left[i : i + 1]
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right_value = right[i : i + 1]
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else:
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left_value = left[i]
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right_value = right[i]
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explanation += [f"At index {i} diff: {left_value!r} != {right_value!r}"]
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break
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if comparing_bytes:
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# when comparing bytes, it doesn't help to show the "sides contain one or more
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# items" longer explanation, so skip it
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return explanation
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len_diff = len_left - len_right
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if len_diff:
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if len_diff > 0:
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dir_with_more = "Left"
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extra = saferepr(left[len_right])
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else:
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len_diff = 0 - len_diff
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dir_with_more = "Right"
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extra = saferepr(right[len_left])
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if len_diff == 1:
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explanation += [f"{dir_with_more} contains one more item: {extra}"]
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else:
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explanation += [
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"%s contains %d more items, first extra item: %s"
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% (dir_with_more, len_diff, extra)
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]
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return explanation
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def _compare_eq_set(
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left: AbstractSet[Any], right: AbstractSet[Any], verbose: int = 0
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) -> List[str]:
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explanation = []
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diff_left = left - right
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diff_right = right - left
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if diff_left:
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explanation.append("Extra items in the left set:")
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for item in diff_left:
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explanation.append(saferepr(item))
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if diff_right:
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explanation.append("Extra items in the right set:")
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for item in diff_right:
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explanation.append(saferepr(item))
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return explanation
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def _compare_eq_dict(
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left: Mapping[Any, Any], right: Mapping[Any, Any], verbose: int = 0
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) -> List[str]:
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explanation: List[str] = []
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set_left = set(left)
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set_right = set(right)
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common = set_left.intersection(set_right)
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same = {k: left[k] for k in common if left[k] == right[k]}
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if same and verbose < 2:
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explanation += ["Omitting %s identical items, use -vv to show" % len(same)]
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elif same:
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explanation += ["Common items:"]
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explanation += pprint.pformat(same).splitlines()
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diff = {k for k in common if left[k] != right[k]}
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if diff:
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explanation += ["Differing items:"]
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for k in diff:
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explanation += [saferepr({k: left[k]}) + " != " + saferepr({k: right[k]})]
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extra_left = set_left - set_right
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len_extra_left = len(extra_left)
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if len_extra_left:
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explanation.append(
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"Left contains %d more item%s:"
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% (len_extra_left, "" if len_extra_left == 1 else "s")
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)
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explanation.extend(
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pprint.pformat({k: left[k] for k in extra_left}).splitlines()
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)
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extra_right = set_right - set_left
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len_extra_right = len(extra_right)
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if len_extra_right:
|
||
|
explanation.append(
|
||
|
"Right contains %d more item%s:"
|
||
|
% (len_extra_right, "" if len_extra_right == 1 else "s")
|
||
|
)
|
||
|
explanation.extend(
|
||
|
pprint.pformat({k: right[k] for k in extra_right}).splitlines()
|
||
|
)
|
||
|
return explanation
|
||
|
|
||
|
|
||
|
def _compare_eq_cls(left: Any, right: Any, verbose: int) -> List[str]:
|
||
|
if not has_default_eq(left):
|
||
|
return []
|
||
|
if isdatacls(left):
|
||
|
import dataclasses
|
||
|
|
||
|
all_fields = dataclasses.fields(left)
|
||
|
fields_to_check = [info.name for info in all_fields if info.compare]
|
||
|
elif isattrs(left):
|
||
|
all_fields = left.__attrs_attrs__
|
||
|
fields_to_check = [field.name for field in all_fields if getattr(field, "eq")]
|
||
|
elif isnamedtuple(left):
|
||
|
fields_to_check = left._fields
|
||
|
else:
|
||
|
assert False
|
||
|
|
||
|
indent = " "
|
||
|
same = []
|
||
|
diff = []
|
||
|
for field in fields_to_check:
|
||
|
if getattr(left, field) == getattr(right, field):
|
||
|
same.append(field)
|
||
|
else:
|
||
|
diff.append(field)
|
||
|
|
||
|
explanation = []
|
||
|
if same or diff:
|
||
|
explanation += [""]
|
||
|
if same and verbose < 2:
|
||
|
explanation.append("Omitting %s identical items, use -vv to show" % len(same))
|
||
|
elif same:
|
||
|
explanation += ["Matching attributes:"]
|
||
|
explanation += pprint.pformat(same).splitlines()
|
||
|
if diff:
|
||
|
explanation += ["Differing attributes:"]
|
||
|
explanation += pprint.pformat(diff).splitlines()
|
||
|
for field in diff:
|
||
|
field_left = getattr(left, field)
|
||
|
field_right = getattr(right, field)
|
||
|
explanation += [
|
||
|
"",
|
||
|
"Drill down into differing attribute %s:" % field,
|
||
|
("%s%s: %r != %r") % (indent, field, field_left, field_right),
|
||
|
]
|
||
|
explanation += [
|
||
|
indent + line
|
||
|
for line in _compare_eq_any(field_left, field_right, verbose)
|
||
|
]
|
||
|
return explanation
|
||
|
|
||
|
|
||
|
def _notin_text(term: str, text: str, verbose: int = 0) -> List[str]:
|
||
|
index = text.find(term)
|
||
|
head = text[:index]
|
||
|
tail = text[index + len(term) :]
|
||
|
correct_text = head + tail
|
||
|
diff = _diff_text(text, correct_text, verbose)
|
||
|
newdiff = ["%s is contained here:" % saferepr(term, maxsize=42)]
|
||
|
for line in diff:
|
||
|
if line.startswith("Skipping"):
|
||
|
continue
|
||
|
if line.startswith("- "):
|
||
|
continue
|
||
|
if line.startswith("+ "):
|
||
|
newdiff.append(" " + line[2:])
|
||
|
else:
|
||
|
newdiff.append(line)
|
||
|
return newdiff
|
||
|
|
||
|
|
||
|
def running_on_ci() -> bool:
|
||
|
"""Check if we're currently running on a CI system."""
|
||
|
env_vars = ["CI", "BUILD_NUMBER"]
|
||
|
return any(var in os.environ for var in env_vars)
|