frosttest

README

This package contains things which are useful for testing code which runs under Ebitengine.

matchesImage.go contains a MatchesImage function which takes a *testing.T, an image name, and an image, and compares the image to the expected output (stored as a .png file in testdata/expected). If it fails to match, or the expected image is missing, it reports a failure to the *testing.T, attempts to write the failed image to testdata/failed (creating the folder if it doesn't exist), and returns false. If it matches, it returns true. It accepts both regular images and *ebiten.Images.

test.go enables testing things under Ebitengine. To do so, you first need a main_test.go file containing:

func TestMain(m *testing.M) {
	frosttest.OnTestMain(m)
}

And then for each test file you have which needs to test something under ebitengine (in Draw or Update or Layout), you can write tests like so:

func Test_SomeTests(t *testing.T) {
	frosttest.QueueLayoutTest(t, test_SomeLayoutTest)
	frosttest.QueueUpdateTest(t, test_SomeUpdateTest)
	frosttest.QueueDrawTest(t, test_SomeDrawTest)	
}

func test_SomeLayoutTest(t *testing.T, outsideWidth, outsideHeight int) (screenWidth, screenHeight int) {
	// Your actual test here. Also return screen dimensions for the Layout function to return:
	return outsideWidth, outsideHeight // you can return something else if you like
}

func test_SomeUpdateTest(t *testing.T) {
	// Your actual test here
}

func test_SomeDrawTest(t *testing.T, screen *ebiten.Image) {
	// Your actual test here
}

You can have multiple tests per file, of course, and they can each queue as many things as they want.

Documentation

Index

• func MatchesImage(t *testing.T, imageName string, img image.Image) bool
• func OnTestMain(m *testing.M)
• func QueueDrawTest(t *testing.T, f func(t *testing.T, screen *ebiten.Image))
• func QueueLayoutTest(t *testing.T, ...)
• func QueueUpdateTest(t *testing.T, f func(t *testing.T))
• type DrawTest
• type DrawTestFunc
• type LayoutTest
• type LayoutTestFunc
• type TestGame
  • func (game *TestGame) Draw(screen *ebiten.Image)
  • func (game *TestGame) Layout(outsideWidth, outsideHeight int) (screenWidth, screenHeight int)
  • func (game *TestGame) Update() (err error)
• type UpdateTest
• type UpdateTestFunc

Functions

func MatchesImage

func MatchesImage(t *testing.T, imageName string, img image.Image) bool

MatchesImage compares an image.Image to "testdata/expected/<imageName>.png". If img is not nil, it attempts to open "testdata/expected/<imageName>.png". If it succeeds, it converts it to an image.Image, and then compares the two images. If it fails, it writes the image to "testdata/failed/<imageName>.png" and raises a test failure. It can handle *ebiten.Images and save them as PNGs. Also returns true if the images match, and false if they don't.

func OnTestMain

func OnTestMain(m *testing.M)

func QueueDrawTest

func QueueDrawTest(t *testing.T, f func(t *testing.T, screen *ebiten.Image))

func QueueLayoutTest

func QueueLayoutTest(t *testing.T, f func(t *testing.T, outsideWidth, outsideHeight int) (screenWidth, screenHeight int))

func QueueUpdateTest

func QueueUpdateTest(t *testing.T, f func(t *testing.T))

Types

type DrawTest

type DrawTest struct {
	// contains filtered or unexported fields
}

type DrawTestFunc

type DrawTestFunc func(t *testing.T, screen *ebiten.Image)

type LayoutTest

type LayoutTest struct {
	// contains filtered or unexported fields
}

type LayoutTestFunc

type LayoutTestFunc func(t *testing.T, outsideWidth, outsideHeight int) (screenWidth, screenHeight int)

type TestGame

type TestGame struct{}

func (*TestGame) Draw

func (game *TestGame) Draw(screen *ebiten.Image)

func (*TestGame) Layout

func (game *TestGame) Layout(outsideWidth, outsideHeight int) (screenWidth, screenHeight int)

func (*TestGame) Update

func (game *TestGame) Update() (err error)

type UpdateTest

type UpdateTest struct {
	// contains filtered or unexported fields
}

type UpdateTestFunc

type UpdateTestFunc func(t *testing.T)