Is it possible to check if an error was raised?

[stephannv]

For example, on RSpec:

def div(a, b)
  raise "Division by 0 error" if b == 0

  a / b
end

describe "#div" do
  context "when b is zero" do
    it "raises error" do
      calculator = Calculator.new

      expect { calculator.div(3, 0) }.to raise_error(RuntimeError)
      # or
      expect { calculator.div(3, 0) }.to raise_error("Division by 0 error")
      # or
      expect { calculator.div(3, 0) }.to raise_error
    end
  end
end

On GDScript I have this class:

class_name Grid

func _init(width: int, height: int) -> void:
  if width % 2 == 0 or height % 2 == 0: assert(false, "Grid must be odd-sized")
  # or
  if width % 2 == 0 or height % 2 == 0: push_error("Grid must be odd-sized")

Is it possible to test this scenario?

[MikeSchulze]

hi @stephannv yes for this scenario you can enable the error to failure reporting in the GdUnit settings.

Report Settings

• Godot
  • Push Error
  • Script Error

It will catch both cases

[stephannv]

@MikeSchulze but will this make test fail? My idea is test be successful, eg.:

assert_lambda(func(): 
  Grid.new(12, 12)
).raise_error("Grid must be odd-sized")

[MikeSchulze]

I do not know this function assert_lambda, who offers this function?

[stephannv]

@MikeSchulze it is just an exemple of what I'm looking for. I think it doesn't exist. I'm looking for a way to assert if error was raised without failing tests

[MikeSchulze]

you can use assert_failure( <lambda>)

assert_failure(func(): assert_str("This is a test message").is_equal("This is a test Message")) \
		.is_failed() \
		.has_message("Expecting:\n 'This is a test Message'\n but was\n 'This is a test Mmessage'")

feel free to join the discord server asking for help

[stephannv]

@MikeSchulze Does it work only if there is an assertion inside proc/lambda? Can I put other things inside? Example:

assert_failure(func(): 
  grid = Grid.new()
  grid.do_something() # this methods raises an error
).is_failed().has_message("Some error message")

[MikeSchulze]

Ok, if I understand you correctly, you want to test if a certain call generates an error and test for it.

class MyClass:
	
	func foo(value :int):
		match value:
			1: assert(false, "foo failed")
			2: push_error("foo failed")

func test_foo():
	assert_error(func(): 
		MyClass.new().foo(0) # success
	).is_success()

	assert_error(func(): 
		MyClass.new().foo(1) # fails by an assert
	).is_failed().has_message("foo failed")
	
	assert_error(func(): 
		MyClass.new().foo(2) # fails by an push_error
	).is_failed().has_message("foo failed")

sorry, for this kind of scenario no asserts exists at the moment, feel free to create a feature request

[stephannv]

Yes, exactly this I was looking for.

Thanks @MikeSchulze for the support.

[MikeSchulze]

@stephannv the next version v4.1.4 will provide the new assert_error
Than you can test for runtime errors

func test_is_success() -> void:
	await assert_error(func (): GodotErrorTestClass.new().test(0)).is_success()


func test_is_assert_failed() -> void:
	await assert_error(func (): GodotErrorTestClass.new().test(1))\
		.is_runtime_error('Assertion failed: this is an assert error')



func test_is_push_warning() -> void:
	await assert_error(func (): GodotErrorTestClass.new().test(2))\
		.is_push_warning('this is an push_warning')


func test_is_push_error() -> void:
	await assert_error(func (): GodotErrorTestClass.new().test(3))\
		.is_push_error('this is an push_error')


func test_is_runtime_error() -> void:
	await assert_error(func (): GodotErrorTestClass.new().test(4))\
		.is_runtime_error("Division by zero error in operator '/'.")

[stephannv]

Nice @MikeSchulze. LGTM