Error Handling in Python
Implement various kinds of error handling and resource management
exercism fetch python error-handling
Implement various kinds of error handling and resource management.
An important point of programming is how to handle errors and close resources even if errors occur.
This exercise requires you to handle various errors. Because error handling is rather programming language specific you'll have to refer to the tests for your track to see what's exactly required.
filelike_objects_are_closed_on_exception function, the
will be an instance of a custom
FileLike class defined in the test suite. This
class implements the following methods:
close, for explicit opening and closing.
__exit__, for implicit opening and closing.
do_something, which may or may not throw an
Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include a message.
To raise a message with an exception, just write it as an argument to the exception type. For example, instead of
raise Exception, you should write:
raise Exception("Meaningful message indicating the source of the error")
Running the tests
To run the tests, run the appropriate command below (why they are different):
- Python 2.7:
- Python 3.3+:
Alternatively, you can tell Python to run the pytest module (allowing the same command to be used regardless of Python version):
python -m pytest error_handling_test.py
-v: enable verbose output
-x: stop running tests on first failure
--ff: run failures from previous test before running other test cases
For other options, see
python -m pytest -h
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exercism debug and looking for the line that starts with
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Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.