TDD Code Katas

Installation

Clone this repository, navigate to the root of the project, and run npm install. To run tests whenever a file changes, run gulp tdd in the terminal.

Other tasks:

• To run a test once, run gulp test in the terminal
• To view unit test code coverage details, ruclearn gulp coverage in the terminal

Practice

There are a number of exercises listed below for you to work through. Practice using test-driven development while solving these code katas. Write out the tests before fleshing out your solutions. Remember to use the minimum amount of code necessary to make all the tests pass, refactoring as necessary (Red-Green-Refactor).

For each of the examples, create a function solving the kata in it's own file inside the src/ directory. Assign it to module.exports so it can used in your test suite, which should reside in it's own file inside the test/ directory (don't forget the .spec suffix). Ex: src/test-name.js gets tested in test/test-name.spec.js.

Exercise 1 - Prime Factors

Note: This has already been completed in src/prime-factors.js and test/prime-factors.spec.js files. It can be used as a reference.

Write a function that will return an array of all the prime factors of any positive integer.

Reference

Remember that a prime factor is a positive integer that is only divisible by itself and 1.

Examples:

1. 2 is only divisible by itself and 1. The function would return [2]

2. 3 is only divisible by itself and 1. The function would return [3]

3. 4 is divisible by 2 and 2

       4
     2 * 2
   

   2 * 2 = 4. The function would return [2, 2]

4. 5 is not divisible by 2 or 3, but only by itself. The function would return [5]

5. 6 is divisible by 2 and 3

       6
     2 * 3
   

   2 * 3 = 6. The function would return [2, 3]

6. 10 is divisible by 2 and 5

       10
     2 * 5
   

   2 * 5 = 10. The function would return [2, 5]

7. 12 is divisible by 2 and 6. 6 is not a prime number, and is divisible by 2

       12
     2 * 6
       2 * 3
   

   2 * 2 * 3 = 12. The function would return [2, 2, 3]

8. 100 is divisible by 2 and 50. 50 is divisible by 2 and 25, 25 is divisible by 5 and 5

       100
     2 * 50
       2 * 25
         5 * 5
   

   2 * 2 * 5 * 5 = 100. The function would return [2, 2, 5, 5]

Exercise 2 - Palindrome

Write a function that will determine if a string, phrase, or number passed in is a palindrome or not. Remember that a palindrome is a value that reads the same forwards and backgrounds.

Rules

1. Function returns a boolean
2. Function allows for multiple words and numbers

Exercise 3 - FizzBuzz

Write a function that will return Fizz if an integer entered is divisible by 3, Buzz if a number entered is divisible by 5, FizzBuzz if a number entered is divisible by 3 and 5, and return the number if not divisible by 3 nor 5.

Exercise 4 - Roman Numerals Converter

Write a function that will convert a positive integer between 1 and 4999 into roman numerals.

Reference

Number	Glyph
1	I
2	II
3	III
4	IV
5	V
6	VI
7	VII
8	VIII
9	IX
10	X
11	XI
12	XII
15	XV
20	XX
30	XXX
40	XL
41	XLI
44	XLIV
50	L
90	XC
100	C
500	D
900	CM
1000	M
4000	MMMM

Exercise 5 - Bowling Game

Write a class that will reproduce a scoring system for a game of bowling. Make two methods:

• roll(pins: int) - called each time a player rolls the ball. The argument is the number of pins knocked down
• score() - called only at the very end of the game and returns an integer of the total score for that game

Ex:

Bowling.roll(3);
Bowling.roll(5);
Bowling.roll(10);
... 
Bowling.score();

Reference

Remember that a game of bowling consists of 10 frames (or rounds). In each frame, a player can take one or two rolls at knocking down the 10 pins, collecting a score of 1 point per pin knocked down. Assuming a player doesn't knock down all the pins on the first roll of the frame, the score for the frame is the number of pins from the first roll plus the number of pins from the second roll. Once all players roll 10 frames, the scores for each player are tallied up and the final score is computed.

Scoring caveats:

• Spares: A spare occurs when a player fails to knock down all of the pins in the first frame, but succeeds in knocking down the remainder in the second frame. The points of that player's next roll are counted and then also added onto the score of the frame where the spare occurred.
  • Ex: Frame 3, roll 1: 8 points. Frame 3, roll 2: 2 points (spare!). Frame 4, roll 1: 8 points, Frame 4, roll 2: 1 point. Score for those two frames would be (10 + 8) + 8 + 1 = 27.
• Strikes: A strike happens when a player knocks down all 10 pins in the first (and only) roll of a frame. The next two rolls are added to the score of the frame where the strike occurred.
  • Ex: Frame 3, roll 1: 10 points (strike! no second roll). Frame 4, roll 1: 8 points. Frame 4 roll 2: 1 point. Score for those two frames would be (10 + 8 + 1) + 8 + 1 = 28.
• In the 10th frame, a player who rolls a spare or a strike may roll the ball extra times to complete the frame, though no more than rolls can occur.

Exercise 6 - String Calculator

Write a function that will accept a string of numbers and return an integer representing the sum of the numbers contained in the string.

Ex: stringCalc('2,3,4') would return 9

Rules

1. An empty string passed in should be interpreted as 0
2. Either comma or \n can be the delimeter
3. Numbers greater than 1000 should be ignored
4. Numbers less than 0 are not allowed

Exercise 7 - Tennis Scoring

Write a function that translates points to the proper tennis score.

Ex: tennisScore(0,2) would return Love-Thirty

Rules

The first player to win 4 points is the winner, unless the score is 3 points to 3 points. Whenever the points are equal (from 3, upwards), the score is called "deuce." If player one scores a point after "deuce," then it is player 1's advantage (a.k.a. "Advantage in"). If player two scores a point after "deuce," then it is "Advantage out". This can go on indefinitely until one player scores two points in a row.

Reference

Points	Score
0-0	Love-All
1-0	Fifteen-Love
1-1	Fifteen-All
2-0	Thirty-Love
2-1	Thirty-Fifteen
2-2	Thirty-All
0-3	Love-Forty
3-3	Deuce
4-0	Winner
4-1	Winner
4-2	Winner
4-3	Advantage In
4-4	Deuce
4-5	Advantage Out
5-5	Deuce
5-6	Advantage Out
6-6	Deuce
7-6	Advantage In
7-7	Deuce
7-8	Advantage Out
7-9	Winner