TDD Exercises

There are lots of Katas available but sometimes even very simple exercises can be enough to practice the basics of TDD.

Some random exercises for practicing minimal steps:

• Create a method that accepts a String and returns an array or list of the words in the String (everything separated by whitespace)
  • "I am hungry" returns ["I", "am", "hungry"]
  • Extension: Only return the first 5 words
  • Extension: Only return unique words
• Create a method that accepts an array or list of Strings. Return an array/list that is sorted by length
  • ["satu", "dua", "empat"] is returned as ["dua", "satu", "empat"]
• Create a method that accepts an array/list of Strings and returns the size of the largest String
  • ["satu", "dua", "empat"] returns 5, the length of the largest word "empat"
• Create a method that calculates the sum/product of all numbers given in a comma separated string
  • "1,2,3,4" returns 10 for sum and 24 for product
• For a class Product create a ProductValidator that returns true if the product is valid (has a name and a price).
  • {'name': 'Ayam Geprek', 'price': '25000.00'} is valid but {}, {'name': 'Soto Ayam'} and {'price': '20000.00'} are not.
• Create a method that gets passed in an array/list of products. Calculate the max price, the min price and the sum.
• Create a method that gets passed in an array/list of products. Return an array/list of all the prices.
• Create a service that accepts a product and writes the JSON representation to a file.

Mocking exercises:

• Create a Service that gets passed in firstname and lastname and persists a Person object in PersonRepository if both of them are set
• Create a Service that gets passed in a comma separated string of names, each of those names should be sent to a Message Queue representation

Katas (there are a lot more of course):

• String Calculator
• Numbers in words
• Roman Numerals