Opt.py.test

#!/usr/bin/env python3

# Copyright (c) 2023 Trevor Taylor
# coding: utf-8
# 
# Permission to use, copy, modify, and/or distribute this software for
# any purpose with or without fee is hereby granted, provided that all
# copyright notices and this permission notice appear in all copies.
# 
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#
import sys
from sys import path
from os.path import dirname
if path[0]==dirname(__file__): path.pop(0)
from xju.cmc import Opt

import contextlib
from typing import Self
from xju.assert_ import Assert
from xju.xn import in_context

_log:list[str]=[]

def log(s: str) -> int:
    _log.append(s)
    print(s,file=sys.stderr)
    return len(_log)

def extract_log() -> list[str]:
    result=_log[:]
    del _log[:]
    return result

class Resource:
    name: str
    entered_at: int|None = None
    exited_at: int|None = None
    ee: None|Exception
    xe: None|Exception

    def __init__(self, name:str, ee:None|Exception, xe:None|Exception):
        self.name = name
        self.ee = ee
        self.xe = xe
        pass

    def __repr__(self):
        return f"Resource({self.name!r})"

    def __enter__(self) -> Self:
        Assert(self.entered_at)==None
        self.entered_at=log(f'+ enter {self.name}')
        if self.ee:
            log(f'E enter {self.name}')
            raise self.ee
        log(f'- enter {self.name}')
        return self
    
    def __exit__(self, t, e, b) -> None:
        try:
            Assert(self.entered_at).isNot(None)
            Assert(self.exited_at).is_(None)
            self.exited_at=log(f'+ exit {self.name}')
            if self.xe:
                log(f'E exit {self.name}')
                raise self.xe
            log(f'- exit {self.name}')
        except Exception:
            raise in_context(f'exit {self.name}') from None
        pass
    pass

def main():
    x = Opt(Resource('c',None,None))
    x.set(Resource('b',None,None))
    v = x.get()
    assert v is not None
    Assert(v.name)=='b'
    x.clear()
    Assert(x.get()).is_(None)
    Assert(extract_log())==[]

    x = Opt(Opt(Resource('c',None,None)))
    x.set(Resource('b',None,None))
    assert v is not None
    Assert(v.name)=='b'
    Assert(repr(x))=="Opt(Resource('b'))"
    x.clear()
    Assert(repr(x))=="Opt(None)"
    Assert(x.get()).is_(None)
    Assert(extract_log())==[]

    x=Opt()
    Assert(extract_log())==[]
    with x as v:
        assert v is None
        x.set(Resource('c',None,None))
        x.set(Resource('b',None,None))
        Assert(extract_log())==[
            '+ enter c', '- enter c',
            '+ enter b', '- enter b',
            '+ exit c', '- exit c'
        ]

    Assert(extract_log())==['+ exit b', '- exit b']

    x=Opt(Resource('c',None,None))
    with x as v:
        assert v is not None
        Assert(v.name)=='c'
        Assert(extract_log())==[
            '+ enter c', '- enter c'
        ]
        x.set(Resource('b',None,None))
        Assert(extract_log())==[
            '+ enter b', '- enter b', '+ exit c', '- exit c'
        ]

    Assert(extract_log())==['+ exit b', '- exit b']

    x=Opt()
    with x:
        x.set(Opt(Resource('c',None,None)))
        x.set(Opt())
        Assert(x.get()).is_(None)
        Assert(extract_log())==['+ enter c', '- enter c', '+ exit c', '- exit c']
        pass
    Assert(extract_log())==[]
    pass
    

main()