round trip test

tests/encode_images.rs

@@ -365,6 +365,7 @@ fn test_multipage_image() {
 /// verify rows per strip setting
 fn test_rows_per_strip() {
     let mut file = Cursor::new(Vec::new());
+    {
         let mut img_encoder = TiffEncoder::new(&mut file).unwrap();
 
         let mut image = img_encoder.new_image::<colortype::Gray8>(100, 100).unwrap();
@@ -375,4 +376,26 @@ fn test_rows_per_strip() {
         let img2: Vec<u8> = vec![0; 2 * 100];
         image.write_strip(&img2[..]).unwrap();
         assert!(image.rows_per_strip(5).is_err());
+        for i in 1..50 {
+            let img2: Vec<u8> = vec![i; 2 * 100];
+            image.write_strip(&img2[..]).unwrap();
+        }
+        assert!(image.write_strip(&img2[..]).is_err());
+    }
+
+    file.seek(SeekFrom::Start(0)).unwrap();
+    {
+        let mut decoder = Decoder::new(&mut file).unwrap();
+        assert_eq!(decoder.get_tag_u64(Tag::RowsPerStrip).unwrap(), 2);
+        assert_eq!(decoder.strip_count().unwrap(), 50);
+
+        for i in 0..50 {
+            let img2 = [i; 2 * 100];
+            if let DecodingResult::U8(data) = decoder.read_strip().unwrap() {
+                assert_eq!(&img2[..], &data[..]);
+            } else {
+                assert!(false);
+            }
+        }
+    }
 }