Add a test for the current search match after the matches change

Search a view, step to the last match, then have the view re-rendered
with fewer matches in it, and the status reads "3 of 1". The positions
are worked out again whenever the content changes, but the index into
them stays where it was. Stepping on from there indexes the positions
out of range and panics.

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

pkg/gocui/search_test.go

@@ -0,0 +1,39 @@
+package gocui
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// writeLines writes the given lines to the view, as a task rendering content into it
+// does: one line at a time.
+func writeLines(v *View, lines ...string) {
+	for _, line := range lines {
+		fmt.Fprintf(v, "%s\n", line)
+	}
+}
+
+func TestSearchStatusAfterTheMatchesChange(t *testing.T) {
+	v := NewView("name", 0, 0, 40, 10, OutputNormal)
+	writeLines(v, "match", "other", "match", "other", "match")
+
+	v.Search("match", nil)
+	_ = v.gotoNextMatch()
+	_ = v.gotoNextMatch()
+	index, total := v.GetSearchStatus()
+	assert.Equal(t, 2, index)
+	assert.Equal(t, 3, total)
+
+	// The content is re-rendered with only the first of those matches left in it.
+	v.Clear()
+	writeLines(v, "match", "other", "other")
+
+	index, total = v.GetSearchStatus()
+	/* EXPECTED:
+	assert.Equal(t, 0, index)
+	ACTUAL: */
+	assert.Equal(t, 2, index)
+	assert.Equal(t, 1, total)
+}