# Tests the code entered by a student in a given practice using a series of

# functions.

#

# To add a test, write a new method with a name starting with `test_`. The

# method should take no argument and return a String: an optional error message.

#

# If the returned string is empty, the test passed. If the string is not empty,

# the test failed.

#

# You can probe the tested scene and script slice using the `_scene` and

# `_slice` properties below.

class_name PracticeTester

extends Reference

# Reference to the tested scene. Use it to test the state of nodes in the scene.

var _scene_root_viewport: Node

# Reference to the edited script slice. Use it to look at the user's code.

var _slice: SliceProperties

var _test_methods := _find_test_method_names()

# We're not using _init() because it doesn't work unless you define it and call the parent's constructor in child classes. It would add boilerplate to every PracticeTester script.

func setup(scene_root: Node, slice: SliceProperties) -> void:

_slice = slice

_scene_root_viewport = scene_root

func get_test_names() -> Array:

return _test_methods.values()

func run_tests() -> TestResult:

var result := TestResult.new()

_prepare()

for method in _test_methods:

var test_name = _test_methods[method]

var error_message: String = call(method)

if error_message != "":

result.errors[test_name] = error_message

else:

# We pass the test name to display it in the interface.

result.passed_tests.push_back(_test_methods[method])

_clean_up()

return result

func _find_test_method_names() -> Dictionary:

var output := {}

var methods := []

for method in get_method_list():

if method.name.begins_with("test_"):

methods.append(method.name)

methods.sort()

for method in methods:

output[method] = method.trim_prefix("test_").capitalize()

return output

# Virtual method.

# Called before running tests.

func _prepare() -> void:

pass

# Virtual method.

# Called after running tests.

func _clean_up() -> void:

pass

class TestResult:

# List of tests passed successfully in the test suite.

var passed_tests := []

var errors := {}

func is_success() -> bool:

return errors.empty()