Refactor a ledger printer.
The ledger exercise is a refactoring exercise. There is code that prints a nicely formatted ledger, given a locale (American or Dutch) and a currency (US dollar or euro). The code however is rather badly written, though (somewhat surprisingly) it consistently passes the test suite.
Rewrite this code. Remember that in refactoring the trick is to make small steps that keep the tests passing. That way you can always quickly go back to a working version. Version control tools like git can help here as well.
Please keep a log of what changes you've made and make a comment on the exercise containing that log, this will help reviewers.
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")To run the tests, run pytest ledger_test.py
Alternatively, you can tell Python to run the pytest module:
python -m pytest ledger_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
Note that, when trying to submit an exercise, make sure the solution is in the $EXERCISM_WORKSPACE/python/ledger directory.
You can find your Exercism workspace by running exercism debug and looking for the line that starts with Workspace.
For more detailed information about running tests, code style and linting, please see Running the Tests.
It's possible to submit an incomplete solution so you can see how others have completed the exercise.