Faketorio

Support library for automated testing of Factorio mods

Purpose

The problem with modding in Factorio (or any other script language based modding environment) is testing. Usually this is solved by a huge amount of manual testing. This amount grows with every new feature and every bugfix.. because in theory you have to test EVERYTHING EVERY.SINGLE.TIME (super annoying).

This is where automated testing comes in. I'm new to lua testing, but there are a couple unit testing frameworks available.

The problem with unit testing is that it only gets you so far. The most interesting aspect (how does it behave in the real game) is hard to mimic.

Enter Faketorio. The goal is to provide a standard system for running your mod against your local Factorio installation, execute tests INSIDE Factorio and then package your mod for release.

Installation

If you use LuaRocks for your lua modules it is as easy as running luarocks install faketorio.

If you do all the dependency management yourself you will have to download the files from this github repo and place them in a convenient location. Then require them with the proper path.

Usage

For a (very) short info on how to interact with faketorio type faketorio -h. For the long version keep reading :)

There are two main aspects of faketorio regarding your mod. The first is mod management and packaging and the second is testing.

Mod management

With Faketorio you can run and build your mod. To do this we need two things: a .faketorio config file in your home folder and a certain folder structure in your mod.

Folder structure

Faketorio assumes the following structure for your mod files:

- MyModFolder/
    - info.json             // the file with all your mod info
    - src/                  // all your mod source files go here (in as many subfolders as you like)
        - control.lua
        - data.lua
        - settings.lua
        - mymod.lua
    - locale/               // all your locale files as described in [aubergine10's guide to localization](https://github.com/aubergine10/Style/wiki/Localisation)
    - spec/                 // all your test files go here (as described by [busted](https://olivinelabs.com/busted/#defining-tests)
        - mod_spec.lua      // normal [busted](https://github.com/Olivine-Labs/busted) unit tests (or any other tests for that matter)
        - mod_feature.lua   // faketorio tests that are run inside of Factorio
    - target/               // temporary folder that faketorio uses to assemble files and folders

The Factorio specific files (control.lua, data.lua, settings.lua, ...) all go into the source folder without any additional subfolders.

.faketorio config file

Faketorio requires a config file to run. You can specify the location with the -c option. If no config path is provided faketorio will search for a file named .faketorio in the current folder. This file has to have three values configured.

factorio_mod_path = "/home/jjurczok/.factorio/mods"
factorio_run_path = "/home/jjurczok/.local/share/Steam/steamapps/common/Factorio/bin/x64/factorio"

# windows based example
factorio_run_path = "D:\Spiele\Factorio\bin\x64\factorio.exe"

faketorio_path = "/usr/share/lua/5.2/faketorio"

factorio_mod_path describes the folder where all your mods are. On my machine this is in the home folder, on windows it will be somewhere else factorio_run_path is the path to the executable (Factorio.exe on windows)

faketorio_path is the path where you installed faketorio itself. If you installed it via luarocks you can find this path with luarocks show faketorio or luarocks doc faketorio

Including custom files

If you want to inlcude custom files into your zip you can specifiy it your .faketorio file like this:

include_files = {
    ["filename"] = "target file name"
}

This will look for filename relative to the current folder. If the file is found it will be copied to target/target file name.

Faketorio commands

With the configuration in place and the mod structured we can now start interacting with faketorio. Faketorio should be run from your mod folder. To do this open a terminal (or command line with start -> execute -> cmd on windows) and navigate to the folder where you do your development (ideally NOT inside the Factorio mods folder ;).

Now you can execute the faketorio commands to interact with your mod and Factorio.

Tests

Now that we covered how to interact with Factorio itself it is time to talk about the real reason for this library. The actual testing.

The tests are inspired by busted and use roughly the same basic principles.

-- in mod_feature.lua
feature("My first feature", function()

    before_scenario(function()
        -- will be called before every scenario in this feature
        -- this is intended for setting up preconditions for this specific feature
    end)

    after_scenario(function()
        -- will be called after every scenario in this feature
        -- this is intended to bring the mod back into a state as it would be expected from the next test
    end)

    scenario("The first scenario", function()
        faketorio.click("todo_maximize_button")
        faketorio.log.info("my first test")
    end)

    scenario("The second scenario", function()
        faketorio.log.info("Scenario 2")
    end)
end)

As described in Folder Structure you can create feature files in your spec folder. These files have to follow the naming pattern <name>_feature.lua. It is best practice to have one feature per file.

In the scenarios you can basically write normal lua code to interact with your mod. Faketorio provides you with some additional functions that you can use.

Running tests ingame

To run your tests inside of Factorio simply invoke faketorio test in a terminal in the mod folder. Faketorio will generate a new map, copy your mod and the tests and starts Factorio.

As soon as you are in game you can open the debug console and enter /faketorio. Simply run the command and all your tests will be executed.

You will see a dialog popping up in the middle of the screen. The top bar indicates progress on feature level, the lower bar indicates progress on scenario level for the currently running feature.

If there are test errors they will be documented in the textbox below the progress bar after the testrun finishes.

Marking tests as success/failure

By default any scenario function that completes is counted as successful. If you want to mark your test as a failure (because some assertion did not work) you can just raise an error

-- in mod_feature.lua
feature("My first feature", function()

    scenario("The first scenario", function()
        faketorio.print("This test is successful.")
    end)

    scenario("The second scenario", function()
        faketorio.print("This test fails.")
        error("test failure")
    end)
end)

At the end of every test run you will receive a report to the console (and the logfile) indicating what worked and what did not. As usual a testrun is only successful if ALL tests pass!

TODO: provide screenshots of success and failure cases

TESTRUN FINISHED: SUCCESS
Run contained 1 features.

Interacting with Factorio

Faketorio provides the following functions

Assertions

The following assertions are provided by faketorio

logging

The log system functions are intended for debug output and if you want to report something to the user while the tests are running.

The system knows four different log levels. TRACE, DEBUG, INFO and WARN. The default log level is INFO. All messages that are logged with a level lower (read left in the list) as the current log level will be ignored.

Messages passed to the logging system will be printed to every player in Factorio. Additionally it will be written to the faketorio.log file in your Factorio script-output folder in your application directory.

To create log messages use one of the following functions

-- simple logging
faketorio.log.trace("my test trace message")
faketorio.log.debug("my test debug message")
faketorio.log.info("my test info message")
faketorio.log.warn("my test warn message")

-- logging with parameter expansion (prints "my test pattern wololo.")
faketorio.log.trace("my test pattern %s.", {"wololo"})
faketorio.log.debug("my test pattern %s.", {"wololo"})
faketorio.log.info("my test pattern %s.", {"wololo"})
faketorio.log.warn("my test pattern %s.", {"wololo"})

-- to change the current log level and thus limiting the output during your tests use
faketorio.log.setTrace()
faketorio.log.setDebug()
faketorio.log.setInfo()
faketorio.log.setWarn()

mocks

Sometimes it is necessary to change the behavior of your mod, pretending certain external events happened. One example would be the user modified the mod settings. As the settings table is read only for the mod we can just mock the result.

Assuming you have a function like this

function myMod.is_setting_enabled(player)
    return settings.get_player_settings(player)["my-mod-setting"].value
end

we can now change the behavior of that function by mocking it:

local player = ...
myMod.is_setting_enabled(player) -- returns true (default value)

-- lets create a mock
when(myMod, "is_setting_enabled"):then_return(false)

myMod.is_setting_enabled(player) -- returns false (the mocked value)

myMod.is_setting_enabled:revert()
myMod.is_setting_enabled(player) -- returns true again (it calls the original function)

Credits

Faketorio is inspired by Factorio stdlib and the work Afforess did there to enhance the testing. Over time I hope to become as complete as this testing system.