# Bowling Score a bowling game. Bowling is a game where players roll a heavy ball to knock down pins arranged in a triangle. Write code to keep track of the score of a game of bowling. ## Scoring Bowling The game consists of 10 frames. A frame is composed of one or two ball throws with 10 pins standing at frame initialization. There are three cases for the tabulation of a frame. * An open frame is where a score of less than 10 is recorded for the frame. In this case the score for the frame is the number of pins knocked down. * A spare is where all ten pins are knocked down by the second throw. The total value of a spare is 10 plus the number of pins knocked down in their next throw. * A strike is where all ten pins are knocked down by the first throw. The total value of a strike is 10 plus the number of pins knocked down in the next two throws. If a strike is immediately followed by a second strike, then the value of the first strike cannot be determined until the ball is thrown one more time. Here is a three frame example: | Frame 1 | Frame 2 | Frame 3 | | :-------------: |:-------------:| :---------------------:| | X (strike) | 5/ (spare) | 9 0 (open frame) | Frame 1 is (10 + 5 + 5) = 20 Frame 2 is (5 + 5 + 9) = 19 Frame 3 is (9 + 0) = 9 This means the current running total is 48. The tenth frame in the game is a special case. If someone throws a strike or a spare then they get a fill ball. Fill balls exist to calculate the total of the 10th frame. Scoring a strike or spare on the fill ball does not give the player more fill balls. The total value of the 10th frame is the total number of pins knocked down. For a tenth frame of X1/ (strike and a spare), the total value is 20. For a tenth frame of XXX (three strikes), the total value is 30. ## Requirements Write code to keep track of the score of a game of bowling. It should support two operations: * `roll(pins : int)` is called each time the player rolls a ball. The argument is the number of pins knocked down. * `score() : int` is called only at the very end of the game. It returns the total score for that game. ## Exception messages 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: ```python 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](https://github.com/pytest-dev/pytest/issues/1629#issue-161422224)): - Python 2.7: `py.test bowling_test.py` - Python 3.3+: `pytest bowling_test.py` Alternatively, you can tell Python to run the pytest module (allowing the same command to be used regardless of Python version): `python -m pytest bowling_test.py` ### Common `pytest` options - `-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` ## Submitting Exercises Note that, when trying to submit an exercise, make sure the solution is in the `$EXERCISM_WORKSPACE/python/bowling` 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 the [help page](http://exercism.io/languages/python). ## Source The Bowling Game Kata at but UncleBob [http://butunclebob.com/ArticleS.UncleBob.TheBowlingGameKata](http://butunclebob.com/ArticleS.UncleBob.TheBowlingGameKata) ## Submitting Incomplete Solutions It's possible to submit an incomplete solution so you can see how others have completed the exercise.