crystal.test

With games having many moving parts and Lua being a dynamic language, the best way to know your code is correct is to run it. As the game grows, it can be difficult or tedious to manually validate that everything is working as intended. Tests are a great way to automate these verifications and to avoid surprise breakages during actual playtests.

Tests can be defined in any .lua file that is part of your game. For example, you could implement and test a class performing additions like this:

local Adder = Class("Adder");

Adder.add = function(self, a, b)
  return a + b;
end

crystal.test.add("Can add numbers", function()
  local adder = Adder:new();
  assert(adder:add(4, 6) == 10);
end);

return Adder;

Tests are executed when the game is launched with the /test command line argument (for example ../bin/lovec.exe . /test). The console output for this command would be:

Running tests

Adder.lua:
  Can add numbers ... ok

Test result: ok. 1/1 tests passed.

Tests are not limited to validating individual classes or functions. They have access to the entire crystal and love APIs, including spawning scenes and simulating player inputs. Since the main game loop is not running during tests, you must manually advance the game simulation by calling update(dt) on your scene or love.update(dt).

Functions

Name	Description
crystal.test.add	Defines a test.
crystal.test.is_running_tests	Returns whether the game is running its test suite or running normally.

Classes

Name	Description
crystal.TestContext	Context object exposing functionality available during tests.