From 3217c5ea8fbaf5520564d43fe770c4fab5038ed0 Mon Sep 17 00:00:00 2001
From: Dan Costinas <danscostinas@gmail.com>
Date: Wed, 22 May 2024 15:01:53 +0300
Subject: [PATCH] Add test

---
 src/contrast.rs | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/src/contrast.rs b/src/contrast.rs
index 92c1c2e8..9267e7fe 100644
--- a/src/contrast.rs
+++ b/src/contrast.rs
@@ -462,6 +462,23 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_adaptive_thesholding_with_delta() {
+        let mut image = GrayImage::from_pixel(3, 3, Luma([100u8]));
+        image.put_pixel(2, 2, Luma::black());
+
+        //big delta should make the theshold for the black pixel small enough to be white
+        let binary = adaptive_threshold_with_delta(&image, 1, 100);
+        let expected = GrayImage::from_pixel(3, 3, Luma::white());
+        assert_pixels_eq!(binary, expected);
+
+        //smaller delta should make the theshold the pixel to be black
+        let binary = adaptive_threshold_with_delta(&image, 1, 50);
+        let mut expected = GrayImage::from_pixel(3, 3, Luma::white());
+        expected.put_pixel(2, 2, Luma::black());
+        assert_pixels_eq!(binary, expected);
+    }
+
     #[test]
     fn test_histogram_lut_source_and_target_equal() {
         let mut histc = [0u32; 256];