Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/importlib_metadata/_context.py: 49%

1from __future__ import annotations 

2 

3import functools 

4import operator 

5 

6 

7# from jaraco.context 6.1 

8class ExceptionTrap: 

9 """ 

10 A context manager that will catch certain exceptions and provide an 

11 indication they occurred. 

12 

13 >>> with ExceptionTrap() as trap: 

14 ... raise Exception() 

15 >>> bool(trap) 

16 True 

17 

18 >>> with ExceptionTrap() as trap: 

19 ... pass 

20 >>> bool(trap) 

21 False 

22 

23 >>> with ExceptionTrap(ValueError) as trap: 

24 ... raise ValueError("1 + 1 is not 3") 

25 >>> bool(trap) 

26 True 

27 >>> trap.value 

28 ValueError('1 + 1 is not 3') 

29 >>> trap.tb 

30 <traceback object at ...> 

31 

32 >>> with ExceptionTrap(ValueError) as trap: 

33 ... raise Exception() 

34 Traceback (most recent call last): 

35 ... 

36 Exception 

37 

38 >>> bool(trap) 

39 False 

40 """ 

41 

42 exc_info = None, None, None 

43 

44 def __init__(self, exceptions=(Exception,)): 

45 self.exceptions = exceptions 

46 

47 def __enter__(self): 

48 return self 

49 

50 @property 

51 def type(self): 

52 return self.exc_info[0] 

53 

54 @property 

55 def value(self): 

56 return self.exc_info[1] 

57 

58 @property 

59 def tb(self): 

60 return self.exc_info[2] 

61 

62 def __exit__(self, *exc_info): 

63 type = exc_info[0] 

64 matches = type and issubclass(type, self.exceptions) 

65 if matches: 

66 self.exc_info = exc_info 

67 return matches 

68 

69 def __bool__(self): 

70 return bool(self.type) 

71 

72 def raises(self, func, *, _test=bool): 

73 """ 

74 Wrap func and replace the result with the truth 

75 value of the trap (True if an exception occurred). 

76 

77 First, give the decorator an alias to support Python 3.8 

78 Syntax. 

79 

80 >>> raises = ExceptionTrap(ValueError).raises 

81 

82 Now decorate a function that always fails. 

83 

84 >>> @raises 

85 ... def fail(): 

86 ... raise ValueError('failed') 

87 >>> fail() 

88 True 

89 """ 

90 

91 @functools.wraps(func) 

92 def wrapper(*args, **kwargs): 

93 with ExceptionTrap(self.exceptions) as trap: 

94 func(*args, **kwargs) 

95 return _test(trap) 

96 

97 return wrapper 

98 

99 def passes(self, func): 

100 """ 

101 Wrap func and replace the result with the truth 

102 value of the trap (True if no exception). 

103 

104 First, give the decorator an alias to support Python 3.8 

105 Syntax. 

106 

107 >>> passes = ExceptionTrap(ValueError).passes 

108 

109 Now decorate a function that always fails. 

110 

111 >>> @passes 

112 ... def fail(): 

113 ... raise ValueError('failed') 

114 

115 >>> fail() 

116 False 

117 """ 

118 return self.raises(func, _test=operator.not_)