Add WordWrap test

util_test.go

@@ -1,7 +1,11 @@
 package cview
 
 import (
+	"strings"
+	"testing"
+
 	"github.com/gdamore/tcell/v2"
+	"github.com/mattn/go-runewidth"
 )
 
 // newTestApp returns a new application connected to a simulation screen.
@@ -17,3 +21,59 @@ func newTestApp(root Primitive) (*Application, error) {
 
 	return app, nil
 }
+
+func TestWordWrap(t *testing.T) {
+	t.Parallel()
+
+	cases := []struct {
+		text          string
+		width         int
+		expectedLines int
+	}{
+		{
+			"first line\n\nthird line",
+			80,
+			3,
+		},
+		{
+			"first line\n\nthird line",
+			6,
+			5,
+		},
+		{
+			"string without any newlines",
+			80,
+			1,
+		},
+		{
+			"string with one newline, string with one newline, string with one>\n<newline, string with one newline",
+			32,
+			5,
+		},
+		{
+			"[red:-:-]Do you[-:-:-] want to\n\nquit the application?",
+			28,
+			4,
+		},
+		{
+			Escape("In [Chinese astronomy], the stars that correspond to Gemini are located in two areas: the [White Tiger of the West] (西方白虎, *Xī Fāng Bái Hǔ*) and the [Vermillion Bird of the South] (南方朱雀, *Nán Fāng Zhū Què*)."),
+			100,
+			3,
+		},
+	}
+	for i, c := range cases {
+		lines := WordWrap(c.text, c.width)
+		for j, line := range lines {
+			if strings.Contains(line, "\n") {
+				t.Errorf("case %d, line %d: wrapped line contains newline", i, j)
+			}
+			strippedWidth := runewidth.StringWidth(string(StripTags([]byte(line), true, true)))
+			if strippedWidth > c.width {
+				t.Errorf("case %d, line %d: wrapped line exceeds width %d with length %d", i, j, c.width, runewidth.StringWidth(line))
+			}
+		}
+		if len(lines) != c.expectedLines {
+			t.Errorf("case %d: expected %d lines, got %d", i, c.expectedLines, len(lines))
+		}
+	}
+}