From 9c0bc5c7da2d60d7fe17bb7206cd523df8a9c958 Mon Sep 17 00:00:00 2001
From: Roman Suvorov <tty2.rs@gmail.com>
Date: Wed, 18 Dec 2024 22:35:57 +0100
Subject: [PATCH] add test for preventing right overscroll

---
 viewport/viewport_test.go | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/viewport/viewport_test.go b/viewport/viewport_test.go
index fd1ee1d..b618ac9 100644
--- a/viewport/viewport_test.go
+++ b/viewport/viewport_test.go
@@ -14,7 +14,7 @@ func TestNew(t *testing.T) {
 		m := New(10, 10)
 
 		if !m.initialized {
-			t.Errorf("on create by New Model should be initialized")
+			t.Errorf("on create by New, Model should be initialized")
 		}
 
 		if m.horizontalStep != defaultHorizontalStep {
@@ -357,3 +357,25 @@ func TestVisibleLines(t *testing.T) {
 		}
 	})
 }
+
+func TestRightOverscroll(t *testing.T) {
+	t.Parallel()
+
+	t.Run("prevent right overscroll", func(t *testing.T) {
+		t.Parallel()
+		content := "Content is short"
+		m := New(len(content)+1, 5)
+		m.SetContent(content)
+
+		for i := 0; i < 10; i++ {
+			m.MoveRight()
+		}
+
+		visibleLines := m.visibleLines()
+		visibleLine := visibleLines[0]
+
+		if visibleLine != content {
+			t.Error("visible line should stay the same as content")
+		}
+	})
+}