Test Array Max

Geoffrey Challen // 2021.10.0

Create a public class TestArrayMax that provides a single void class method named test. test accepts a single parameter: an instance of ArrayMax.

Each ArrayMax provides a method max that accepts an int[] and returns the maximum of the values as an int. If the array is null or empty max should throw an IllegalArgumentException.

However, some ArrayMax implementations are broken! Your job is to identify all of them correctly. To do this you should use assert to test various inputs. (Do not throw other kinds of exceptions on failure.)

Here's an example:

Your function does not need to return a value. Instead, if the code is correct no assertion should fail, and if it is incorrect one should.

As you design test inputs, here are two conflicting objectives to keep in mind:

  • Less is more. The fewer inputs you need to identify all broken cases, the more readable your test suite will be.
  • Think defensively. At the same time, you want to anticipate all the different mistakes that a programmer might make. You've probably made many of these yourself! Examples include forgetting to check for null, off-by-one errors, not handling special cases properly, etc.

You'll also need to think about how to use try-catch to handle places where the code should throw an exception, how to ensure that it does, and how to make sure it throws the right type.

Good luck and have fun!