65 lines
2.5 KiB
Markdown
65 lines
2.5 KiB
Markdown
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# Hello World
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The classical introductory exercise. Just say "Hello, World!".
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["Hello, World!"](http://en.wikipedia.org/wiki/%22Hello,_world!%22_program) is
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the traditional first program for beginning programming in a new language
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or environment.
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The objectives are simple:
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- Write a function that returns the string "Hello, World!".
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- Run the test suite and make sure that it succeeds.
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- Submit your solution and check it at the website.
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If everything goes well, you will be ready to fetch your first real exercise.
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## Exception messages
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Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to
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indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not
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every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include
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a message.
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To raise a message with an exception, just write it as an argument to the exception type. For example, instead of
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`raise Exception`, you should write:
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```python
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raise Exception("Meaningful message indicating the source of the error")
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```
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## Running the tests
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To run the tests, run the appropriate command below ([why they are different](https://github.com/pytest-dev/pytest/issues/1629#issue-161422224)):
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- Python 2.7: `py.test hello_world_test.py`
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- Python 3.4+: `pytest hello_world_test.py`
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Alternatively, you can tell Python to run the pytest module (allowing the same command to be used regardless of Python version):
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`python -m pytest hello_world_test.py`
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### Common `pytest` options
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- `-v` : enable verbose output
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- `-x` : stop running tests on first failure
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- `--ff` : run failures from previous test before running other test cases
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For other options, see `python -m pytest -h`
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## Submitting Exercises
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Note that, when trying to submit an exercise, make sure the solution is in the `$EXERCISM_WORKSPACE/python/hello-world` directory.
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You can find your Exercism workspace by running `exercism debug` and looking for the line that starts with `Workspace`.
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For more detailed information about running tests, code style and linting,
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please see [Running the Tests](http://exercism.io/tracks/python/tests).
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## Source
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This is an exercise to introduce users to using Exercism [http://en.wikipedia.org/wiki/%22Hello,_world!%22_program](http://en.wikipedia.org/wiki/%22Hello,_world!%22_program)
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## Submitting Incomplete Solutions
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It's possible to submit an incomplete solution so you can see how others have completed the exercise.
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