10.14 Unit Testing

since Haxe 4.0.0

Deprecated: The unit testing API has been removed from the standard library in Haxe 4. For compatibility purposes it is still available in the hx3compat library. See Haxe 3 Compatibility.

The Haxe Standard Library provides basic unit testing classes from the haxe.unit package.

Creating new test cases

First, create a new class extending haxe.unit.TestCase and add own test methods. Every test method name must start with "test".

class MyTestCase extends haxe.unit.TestCase {
  public function testBasic() {
    assertEquals("A", "A");
Running unit tests

To run the test, an instance of haxe.unit.TestRunner has to be created. Add the TestCase using the add method and call run to start the test.

class Main {
  static function main() {
    var r = new haxe.unit.TestRunner();
    r.add(new MyTestCase());
    // add other TestCases here

    // finally, run the tests

The result of the test looks like this:

Class: MyTestCase
OK 1 tests, 0 failed, 1 success
Test functions

The haxe.unit.TestCase class comes with three test functions.

  • assertEquals(expected, actual) Succeeds if expected and actual are equal
  • assertTrue(a) Succeeds if a is true
  • assertFalse(a) Succeeds if a is false
Setup and tear down

To run code before or after the test, override the functions setup and tearDown in the TestCase.

  • setup is called before each test runs.
  • tearDown is called once after all tests are run.
class MyTestCase extends haxe.unit.TestCase {
  var value:String;

  override public function setup() {
    value = "foo";

  public function testSetup() {
    assertEquals("foo", value);
Comparing Complex Objects

With complex objects, it can be difficult to generate expected values to compare to the actual ones. It can also be a problem that assertEquals doesn't do a deep comparison. One way around these issues is to use a string as the expected value and compare it to the actual value converted to a string using Std.string. Below is a trivial example using an array.

public function testArray() {
  var actual = [1,2,3];
  assertEquals("[1, 2, 3]", Std.string(actual));
Run unit test

This is an example showing how to run your unit tests (on Neko and Node.js) after compilation using a HXML.

-p source/main/haxe
-p source/test/haxe
--main your.package.TestRunnerMain

--neko output/neko/test.n
--cmd neko ./output/neko/test.n

--js output/javascript/test.js
--cmd node ./output/javascript/test.js
Related content
  • See the haxe.unit package on the API documentation for more details.