Add tests for drawing search matches

No test checks yet which cells draw shows as search matches. The next
commit changes how draw works this out.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pkg/gocui/search_test.go

@@ -57,6 +57,120 @@ func BenchmarkWriteToSearchedView(b *testing.B) {
 	}
 }
 
+// drawSearchHighlights draws the view and returns how each of its rows is highlighted:
+// "#" for a search match, "*" for the current one, and "." for neither.
+func drawSearchHighlights(v *View) []string {
+	v.draw(true)
+
+	width, height := v.InnerSize()
+	rows := make([]string, 0, height)
+	for y := range height {
+		row := ""
+		for x := range width {
+			_, style, _ := Screen.Get(v.x0+x+1, v.y0+y+1)
+			switch style.GetBackground() {
+			case getTcellColor(ColorYellow, OutputNormal):
+				row += "#"
+			case getTcellColor(ColorCyan, OutputNormal):
+				row += "*"
+			default:
+				row += "."
+			}
+		}
+		rows = append(rows, row)
+	}
+	return rows
+}
+
+// The search matches on screen are highlighted, and the current one in a color of its
+// own.
+func TestDrawSearchMatches(t *testing.T) {
+	WithSimulationScreen(t, 14, 6)
+
+	v := NewView("name", 0, 0, 11, 5, OutputNormal) // InnerWidth 10, InnerHeight 4
+	writeLines(v,
+		"ab",
+		"abab xab",
+		"no match",
+		"xxxxxxxxxab xxxxx ab",
+		"ab ab",
+		"ab",
+	)
+	v.Search("ab", nil)
+	_ = v.gotoNextMatch()
+	_ = v.gotoNextMatch()
+	index, total := v.GetSearchStatus()
+	assert.Equal(t, 2, index, "the current match is the second one in the second line")
+	assert.Equal(t, 9, total)
+
+	// Scrolled down past the first line, so that the last line is off screen too.
+	v.SetOriginY(1)
+	assert.Equal(t,
+		[]string{
+			"##**..##..", // abab xab
+			"..........", // no match
+			".........#", // xxxxxxxxxa
+			"##.##.....", // ab ab
+		},
+		drawSearchHighlights(v))
+
+	// Scrolled sideways, matches show where they are partly on screen.
+	v.SetOriginX(3)
+	assert.Equal(t,
+		[]string{
+			"*..##.....", // b xab
+			"..........", // match
+			"......##..", // xxxxxxab x
+			"##........", // ab
+		},
+		drawSearchHighlights(v))
+}
+
+// Where matches overlap, a cell is highlighted as part of the first match it is in.
+func TestDrawOverlappingSearchMatches(t *testing.T) {
+	WithSimulationScreen(t, 14, 6)
+
+	v := NewView("name", 0, 0, 11, 2, OutputNormal) // InnerWidth 10, InnerHeight 1
+	writeLines(v, "aaaa")
+	v.Search("aa", nil)
+	_ = v.gotoNextMatch()
+	index, total := v.GetSearchStatus()
+	assert.Equal(t, 1, index, "the current match is the one in the middle")
+	assert.Equal(t, 3, total)
+
+	assert.Equal(t,
+		[]string{"##*#......"},
+		drawSearchHighlights(v))
+}
+
+// The model can find a match that the view doesn't show, for example in a commit hash
+// that the view abbreviates. Such a match is highlighted where the model says it is.
+// The other matches are highlighted where the view shows them.
+func TestDrawSearchMatchesFromTheModel(t *testing.T) {
+	WithSimulationScreen(t, 14, 6)
+
+	v := NewView("name", 0, 0, 11, 4, OutputNormal) // InnerWidth 10, InnerHeight 3
+	writeLines(v, "ab ab", "1234567", "ab")
+	v.Search("ab", []SearchPosition{
+		{XStart: 2, XEnd: 6, Y: 0},
+		{XStart: 2, XEnd: 6, Y: 1},
+		{XStart: 2, XEnd: 6, Y: 2},
+	})
+	_ = v.gotoNextMatch()
+	_ = v.gotoNextMatch()
+	index, total := v.GetSearchStatus()
+	assert.Equal(t, 2, index, "the current match is the one the view doesn't show")
+	assert.Equal(t, 4, total)
+
+	assert.Equal(t,
+		[]string{
+			"##.##.....", // ab ab
+			"..****....", // 1234567
+			"##........", // ab
+		},
+		drawSearchHighlights(v))
+}
+
 func BenchmarkDrawViewWithManySearchMatches(b *testing.B) {
 	WithSimulationScreen(b, 102, 42)
 	v := NewView("name", 0, 0, 101, 41, OutputNormal)