This repository contains a simple Python 3 module that implements the well-known shunting-yard algorithm. This algorithm allows the conversion of a mathematical expression written using the familiar infix notation into an equivalent expression written in postfix notation. You can find out more about this algorithm from the sources below.
- https://en.wikipedia.org/wiki/Shunting-yard_algorithm
- http://www.oxfordmathcenter.com/drupal7/node/628
The module, found in shunting_yard.py contains a function called
infixToPostfix, which implements the basic algorithm, along with a number
of helper functions. I suggest testing each helper function in isolation
since they are written so as not to depend upon one another.
I have included a script called demo.sh that provides several small manual
functional test cases and demonstrates how to run the module as a command
line program. This is purely for those who may be interested (and for my own
testing). You don't need to worry about functional testing and you shouldn't
make any changes to the module code.
I will execute the script called runtests.sh to run your unit tests. I have
populated this file with a command that should be sufficient. However, if you
find that you'd like me to run your tests using a different command, simply
modify the script accordingly.
Run the script like this: ./runtests.sh.
By default, any files that match the pattern test*.py where * is a
wildcard meaning "anything", will be searched for tests. I have added a
single test for the tokenize function as an example to get you started.
I will make several modifications to the module code to introduce bugs in different functions. Your tests should "catch" these bugs. In other words, if I add a bug in a given function, one or more of your tests for that function should fail when I run the tests afterward.