simple-calculator part 2

Story points 8
Tags tdd
Hard Prerequisites
  • PROJECTS: simple-calculator part 1

    • This a continuation of PROJECTS: simple-calculator part 1 . If you haven’t done that yet then please do. At this point you should have a well tested add and multiply function.

    This exercise will require a little OOP knowledge. Brace yourself.

    Set up your environment

    Javascript

    Please test your code using jasmine.

    Your directory structure should look like this.

        >node_modules    <---- make sure this is in your .gitignore
    >spec
        > support
            - jasmine.json
        - string_calculator_spec.js
    >src
        - string_calculator.js
    - package.json

    Python

    Your project is expected to be completed using pytest. You are expected to follow industry best practices in all things. This means that you need to have a directory structure that is in good shape. Please name your files and folders like this:

    ├── simple_calculator   the package under test
│   └── calculator.py
├── requirements.txt    installation requiremnts
├── setup.py            installation script for the package under test
└── tests               all package tests go in this directory
    └── test_calculator.py

    Please take a look at this topic to see an explanation of the required directory structure. : [TODO] Umuzi Tech Department

    Introducing the calculator class

    Update your tests so that they expect the add and multiply functions to be part of a class. Now make those tests pass.

    For now on this document will just describe the features we need the Calculator to have. You need to figure out the tests and implementation yourself.

    Note

    This is an extension of PROJECTS: simple-calculator part 1 . In other words, previously implemented functionality should still work.

    # this should still work
calculator_instance.add(3,5) # should return 8
calculator_instance.multiply(30,2) # should return 60

# and multiple arguments should work too
calculator_instance.add(3,5,2) # should return 10

    The multiply functionality should also still work.

    Remember the last result

    The calculator should have a function called last that returns the last result. Example usage:

    calculator_instance.add(1,2)
calculator_instance.last() # should return 3

    Use the last result in other calculations

    The add and multiply functions should allow "LAST" as a parameter.

    Example usage:

    calculator_instance.add(1,2)
calculator_instance.multiply("LAST",5) # should return 15

    Memory Slots

    Allow the calculator to remember more stuff by implementing a set_slot function. The set_slot function should take a single number as an argument. That argument is called the slot number. Also implement get_slot for getting the value from a memory slot. Neither get_slot or set_slot should effect the output of last.

    Example usage:

    calculator_instance.add(1,2)
calculator_instance.set_slot(1)
calculator_instance.get_slot(1) # should return 3
calculator_instance.add(10,20)

calculator_instance.set_slot(2)
calculator_instance.get_slot(2) # should return 30

calculator_instance.add(100,200) # returns 300. The "last" value is updated
calculator_instance.get_slot(1) # should return 3
calculator_instance.get_slot(2) # should return 30
calculator_instance.last() # should return 300

    Allow the use of memory slots and LAST as arguments

    The add and multiply functions should allow memory slots as parameters. If we were using memory slot 5 as an argument then we would represent it like this "SLOT_5".

    Example usage: Following from the previous example:

    calculator_instance.add(100,200) # returns 300. The "last" value is updated
calculator_instance.get_slot(1) # should return 3
calculator_instance.get_slot(2) # should return 30
calculator_instance.last() # should return 300 (just like before)

# THE FOLLOWING FUNCTIONALITY SHOULD WORK

calculator_instance.add("LAST",10) # should return 310 (= 300 + 10)
calculator_instance.add("SLOT_1",5) # should return 8 (= 3 + 5)
calculator_instance.multiply("SLOT_2",2) # should return 60 (= 30 * 2)
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