From a557386dec65099c7ae3c9a5694fb42baf9b354d Mon Sep 17 00:00:00 2001
From: "Sergey \"Shnatsel\" Davidoff" <shnatsel@gmail.com>
Date: Sun, 1 Dec 2024 08:31:49 +0000
Subject: [PATCH] Add an equivalence test for the Paeth implementations

---
 src/filter.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/filter.rs b/src/filter.rs
index 856008ec..c56ff84a 100644
--- a/src/filter.rs
+++ b/src/filter.rs
@@ -1157,6 +1157,18 @@ mod test {
         }
     }
 
+    #[test]
+    fn paeth_impls_are_equivalent() {
+        use super::{filter_paeth, filter_paeth_decode};
+        for a in 0..=255 {
+            for b in 0..=255 {
+                for c in 0..=255 {
+                    assert_eq!(filter_paeth(a, b, c), filter_paeth_decode(a, b, c));
+                }
+            }
+        }
+    }
+
     #[test]
     fn roundtrip_ascending_previous_line() {
         // A multiple of 8, 6, 4, 3, 2, 1