add tests for CursorMove::Forward and CursorMove::Back

tests/cursor.rs

@@ -0,0 +1,68 @@
+use tui_textarea::{CursorMove, TextArea};
+
+const BOTTOM_RIGHT: CursorMove = CursorMove::Jump(u16::MAX, u16::MAX);
+
+#[test]
+fn test_empty_textarea() {
+    use CursorMove::*;
+
+    let mut t = TextArea::default();
+    for m in [
+        Forward,
+        Back,
+        Up,
+        Down,
+        Head,
+        End,
+        Top,
+        Bottom,
+        WordForward,
+        WordBack,
+        ParagraphForward,
+        ParagraphBack,
+        Jump(0, 0),
+        Jump(u16::MAX, u16::MAX),
+    ] {
+        t.move_cursor(m);
+        assert_eq!(t.cursor(), (0, 0), "{:?}", m);
+    }
+}
+
+#[test]
+fn test_forward() {
+    let mut t = TextArea::from(["abc", "def"]);
+
+    for pos in [
+        (0, 1),
+        (0, 2),
+        (0, 3),
+        (1, 0),
+        (1, 1),
+        (1, 2),
+        (1, 3),
+        (1, 3),
+    ] {
+        t.move_cursor(CursorMove::Forward);
+        assert_eq!(t.cursor(), pos);
+    }
+}
+
+#[test]
+fn test_back() {
+    let mut t = TextArea::from(["abc", "def"]);
+    t.move_cursor(BOTTOM_RIGHT);
+
+    for pos in [
+        (1, 2),
+        (1, 1),
+        (1, 0),
+        (0, 3),
+        (0, 2),
+        (0, 1),
+        (0, 0),
+        (0, 0),
+    ] {
+        t.move_cursor(CursorMove::Back);
+        assert_eq!(t.cursor(), pos);
+    }
+}