This is a collection of katas I've collected from various user group meetups, books, videos, and conferences I've attended over time. I have attributed the source as best as I can determine for these katas in their description.

I am borrowing the structure of this repository from Dan Wiebe's Scala_Katas. He describes the structure as follows:

Note

There are several branches in this repository:

• master: Contains skeleton tests and skeleton production code for each of the katas listed here. All the tests fail. You can use the existing code and tests to build your solution on, or you can completely replace some or all of it.
• all the others: Each kata has its own branch. If you check out the branch for a particular kata, all the code for the other katas will disappear, and you'll see a possible solution for the selected kata. All the tests pass. In all cases, there are other solutions; there may even be better solutions. The ones provided are solutions, but not the solutions.

From the Columbus Scala User Group's repo of katas is a simple kata to determine different types of triangles.

Using TDD, write a method or function that accepts three numbers as the lengths of three line segments. Determine computationally which of the following cases are true:

The three segments

1. Can be joined into an equilateral triangle. (example: 3, 3, 3)
2. Can be joined into an isosceles triangle. (example: 5, 5, 3);
3. Can be joined into a right triangle. (example: 3, 4, 5);
4. Can only be joined into a triangle that is not one of the preceding cases. (example: 2, 3, 4)
5. Cannot be made into a triangle. (example: 2, 3, 5) [Warning: might look isosceles at first glance.]

The order in which the segments are supplied must not affect the result.

A timeless classic. One of the origin stories for this kata is that it models a playground game where children took turns saying sequential numbers, but substituting the words Fizz and/or Buzz when the number was a multiple of 3 and/or 5.

This kata is a popular white boarding exercise, to a point where it is almost a white boarding cliche. This kata is great for practicing small steps, writing the most basic code needed to make a unit test pass, and refactoring.

Here are the rules for this kata:

• Write a method that takes an integer and returns a string. This represents the act of saying a number.
• The string should be the numerical characters that represent the value of the integer that was passed, EXCEPT:
  • When the integer passed is a multiple of 3, the method should say Fizz.
  • When the integer passed is a multiple of 5, the method should say Buzz.

There are some variations that are good to implement once you have these basic rules implemented.

• Implement a method that takes a lower boundary integer and a upper boundary integer and return a list of the spoken words from the integers inbetween those boundaries.
• Practice changing requirements:
  • Change the number associated with Fizz to 4 or another value.
  • Add a third word, "BANG" for multiples of 11.
• Implement restrictions on the method input, for example limit the integers to positive integers.

Today's gig economy is disrupting industries around the world. This kata pays homage to one of the original gig jobs. The goal is to write a method that calculates the pay for a babysitter's shift.

• The babysitter

  • starts no earlier than 5:00PM.
  • leaves no later than 4:00AM.
  • gets paid $12/hour from the start of their shift to the children's bedtime.
  • gets paid $8/hour from bedtime to midnight.
  • gets paid $16/hour from midnight to the end of their shift.
  • will start their shift on the hour and end their shift on the hour.

• The bedtime

  • will be between 8:00PM and 11:00PM.
  • can be before the start of the babysitter's shift.
  • can be after the end of the babysitter's shift.

As a babysitter,

In order to get paid for 1 night of work,

I want to calculate my nightly wage.

Create a method that takes the babysitter's start time, end time, and the children's bedtime and returns the amount that the babysitter is owed for that shift. You should use military/24 hour format for the start/end times.

• Create a minimum wage rule and ensure that the babysitter does not receive pay that falls below the minimum wage for the entire shift. For example a minimum wage of $9:
  • With one hour pre-bedtime and four hours pre midnight/post bedtime hours would pay $45.
  • With one hour pre-bedtime and one hour pre midnight/post bedtime hours would remain $20.
• Allow partial hour pay and take start/end times as String arguments.