Add some missing tests

internal/ui/editor.go

@@ -110,7 +110,7 @@ func (e *editor) pixAt(x, y int) []uint8 {
 	iy := y / e.zoom
 
 	if ix >= e.img.Bounds().Dx() || iy >= e.img.Bounds().Dy() {
-		return []uint8{0, 0, 0, 128}
+		return []uint8{0, 0, 0, 0}
 	}
 
 	return colorToBytes(e.img.At(ix, iy))

internal/ui/editor_test.go

@@ -1,6 +1,7 @@
 package ui
 
 import (
+	"image"
 	"image/color"
 	"io/ioutil"
 	"os"
@@ -73,6 +74,29 @@ func TestEditor_Save(t *testing.T) {
 	assert.Equal(t, red, e.PixelColor(0, 0))
 }
 
+func TestEditorFGColor(t *testing.T) {
+	e := NewEditor()
+
+	assert.Equal(t, color.Black, e.FGColor())
+}
+
+func TestEditor_SetFGColor(t *testing.T) {
+	e := NewEditor()
+
+	fg := color.White
+	e.SetFGColor(fg)
+	assert.Equal(t, fg, e.FGColor())
+}
+
+func TestEditor_PixelColor(t *testing.T) {
+	file := testFile("8x8")
+	e := NewEditor()
+	e.LoadFile(file)
+
+	assert.Equal(t, color.RGBA{A: 255}, e.PixelColor(0, 0))
+	assert.Equal(t, color.RGBA{R: 0, G: 0, B: 0, A: 0}, e.PixelColor(9, 9))
+}
+
 func TestEditor_SetPixelColor(t *testing.T) {
 	file := testFile("8x8")
 	e := NewEditor()
@@ -83,3 +107,11 @@ func TestEditor_SetPixelColor(t *testing.T) {
 	e.SetPixelColor(1, 1, col)
 	assert.Equal(t, col, e.PixelColor(1, 1))
 }
+
+func TestEditor_fixEncoding(t *testing.T) {
+	size := 4
+	nonRGBA := image.NewCMYK(image.Rect(0, 0, size, size))
+
+	fixed := fixEncoding(nonRGBA)
+	assert.Equal(t, image.Rect(0, 0, size, size), fixed.Bounds())
+}