Wurst Unit

Last updated: March 25, 2019


Wurst Unit


We already discussed unit testing in BOTW 4 so let’s take a closer look at the package.

Magic functions

The first three functions of the package are annotated with @compiletimenative and the latter two have no implementation. They have that annotation to indicate that they are a custom native that is implemented inside the wurst compiler and only available at compiletime, disjuct from warcraft and Jass. In case of println it has an implementation when used in Jass (DisplayTimedTextToPlayer) but another one at runtime, inside the compiler.

@compiletimenative public function println(string msg)
	DisplayTimedTextToPlayer(GetLocalPlayer(), 0, 0, 60, msg)
@compiletimenative public function testFail(string msg)
@compiletimenative public function testSuccess()

println is just a function to print something to vscode’s output tab. You can use it and print to perform logs in your code that will show up in tests. testFail and testSuccess are the functions that make a unit test fail or succeed, depending on which one is called first. Tests succeed by default and you should thus make sure to use asertions instead of these natives directly.


After the compiletime natives we have a list of assertXX functions that build upon testFail and testSuccess, providing better API and debug output. As by code conventions you should prefer the typed extension functions over the lower level ones. Let’s look at one example, first a not ideal assertion of two integers:

// Not ideal
assertTrue(someInt == someOtherInt)

If the test fails, you will only get a failed assertion without further information:

FAILED assertion:
Test failed: Assertion failed

On the other hand if you use the proper assertion:

// Better

The result will be better styled code and improved debug output:

FAILED assertion:
Test failed: Expected <2>, Actual <1>

To make assertions on custom data types you can write a custom assertEquals extension function for that class. Just take a look at the existing ones and duplicate the functionality.

class MyData
	var x = 0
	var p = players[0]

public function MyData.assertEquals(MyData expected) returns boolean
		if  this.x != expected.x or this.p != expected.p
			testFail("Expected <" + expected.toString() + ">, Actual <" + this.toString() + ">")