Diamond Challenge

Table of Contents

1. Introduction

2. Functions

   2.1 print_diamond()
   2.2 build_diamond()
   2.3 validate_input()

3. Unit Tests

4. Automated Test Cases

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1. Introduction

The diamond_challenge module takes a letter as an input, either on the command line, or via the the keybord after the start of the script, and prints a diamond, starting with 'A' at the top, and the supplied letter at the widest point.

It was developed using Python 2.7, but also works with Python 3.

The following is an example usage for supplying a letter on the command line:

python diamond_challenge.py E

The script will then print out the following:

    A
   B B
  C   C
 D     D
E       E
 D     D
  C   C
   B B
    A

Input can also be accepted at run-time. By using python diamond_challenge.py, the program will request an input via the following prompt:

    Enter a letter to create the diamond:

If a valid input is given, the program will print the diamond. If not, an error message will be generated, and the program will exit. This could easily be customized to handle errors the way the user wants.

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2. Functions:

2.1 print_diamond(letter):

Inputs: str letter: A capital letter, which will be used as the widest point of the diamond.

print_diamond takes the an input of a capital letter, and prints a diamond of letters starting with 'A' at the top and bottom point, and the provided letter at the right and left points. This is the most generic function that calls all verificationand building functions. It is also responsible for printing the resulting diamond.

For example, if 'D' is provided, the following will be printed:

   A
  B B
 C   C
D     D
 C   C
  B B
   A

If 'A' is input, a diamond cannot be generated, so a single line with 'A' is printed.

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2.2 build_diamond(letter):

Inputs: str validated_letter: A capital letter, that will be used to generate the list of strings needed to print out the diamond.

Returns: A list a strings that contains the correct spacing for printing the diamond.

build_diamond is used to generate the list of strings needed to print the diamond structure. It takes a single argument of a letter (in string format), and returns a list of strings.

This list of strings can then be printed with newline characters (using join) to output the diamond structure.

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2.3 validate_input(input_string):

Inputs: str input_string: A string input to the program for validation that it will work wiht the diamond_challenge program.

Returns: True if the string can be used to create a diamond. False if cannot be used.

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3. Unit Tests

Unit tests are provided with the program to test the functionality. They can be run from the command line by entering:

python -m unittest diamond_challenge_unittest

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4. Automated Test Cases

Automated tests cases are provided via shell and batch files which can be run on Unix and Windows machines repsectively. They generate an example output in the file test_output.txt with some interesting test cases. The output of the automated test cases is provided, but will be regnerated with each run of the shell/batch scripts.

Copyright (C) 2018, Luke Welch