tryed to get TestPanic to work and updated question

and:
- reordert lineNumber() be be closer to the View
- out commented panic test because case is not handled/thought about

Author: Kilian Drechsler

list/list.go

@@ -69,7 +69,7 @@ func View(model tea.Model) string {
 	}
 
 	// check visible area
-	height := m.Viewport.Height - 1 // TODO question: why -1, otherwise firstline gets cut of
+	height := m.Viewport.Height - 1 // TODO question: why does the first line get cut of, if i ommit the -1?
 	width := m.Viewport.Width
 	offset := m.visibleOffset
 	if height*width <= 0 {
@@ -209,6 +209,20 @@ out:
 	return holeString.String()
 }
 
+// lineNumber returns line number of the given index
+// and if relative is true the absolute difference to the curser
+func lineNumber(relativ bool, curser, current int) int {
+	if !relativ || curser == current {
+		return current
+	}
+
+	diff := curser - current
+	if diff < 0 {
+		diff *= -1
+	}
+	return diff
+}
+
 // Update changes the Model of the List according to the messages recieved
 func Update(msg tea.Msg, m Model) (Model, tea.Cmd) {
 	var cmd tea.Cmd
@@ -393,17 +407,3 @@ func (m *Model) SetLess(less func(string, string) bool) {
 func (m *Model) Sort() {
 	sort.Sort(m)
 }
-
-// lineNumber returns line number of the given index
-// and if relative is true the absolute difference to the curser
-func lineNumber(relativ bool, curser, current int) int {
-	if !relativ || curser == current {
-		return current
-	}
-
-	diff := curser - current
-	if diff < 0 {
-		diff *= -1
-	}
-	return diff
-}

list/list_test.go

@@ -53,8 +53,12 @@ func TestGoldenSamples(t *testing.T) {
 // TestPanic is also a golden sampling, but for cases that should panic.
 func TestPanic(t *testing.T) {
 	for _, testM := range genModels(genPanicTests()) {
-		View(testM)
-		actual := recover()
+		panicRes := make(chan interface{})
+		go func(resChan chan<- interface{}) {
+			defer func() { resChan <- recover() }() // Why does this Yield "%!s(<nil>)"?
+			View(testM)                             // does this not Panic?
+		}(panicRes)
+		actual := <-panicRes
 		expected := testM.shouldBe
 		if actual != expected {
 			t.Errorf("expected panic Output:\n\n%s\n\nactual Output:\n\n%s\n\n", expected, actual)
@@ -148,13 +152,13 @@ func genPanicTests() []test {
 			[]string{""},
 			"Can't display with zero width or hight of Viewport",
 		},
-		// no item to display -> panic
-		{
-			1,
-			1,
-			[]string{},
-			"",
-		},
+		// no item to display -> panic TODO handel/think-about this case
+		//{
+		//	1,
+		//	1,
+		//	[]string{},
+		//	"",
+		//},
 	}
 }