split regression tests

tests/dither.rs

@@ -35,22 +35,29 @@ fn compare_original(sample_file: &str, reference_file: &str, method: &DitherMeth
 
     Ok(())
 }
+
 #[test]
-fn test_sample_images() -> Result<()> {
+fn sample_0_atkinson() -> Result<()> {
     compare_original(
         "sample_0.tiff",
         "sample_0_atkinson.tiff",
         &DitherMethod::Atkinson,
-    )?;
+    )
+}
+#[test]
+fn sample_1_atkinson() -> Result<()> {
     compare_original(
         "sample_1.tiff",
         "sample_1_atkinson.tiff",
         &DitherMethod::Atkinson,
-    )?;
+    )
+}
+
+#[test]
+fn sample_1_floydsteinberg() -> Result<()> {
     compare_original(
         "sample_1.tiff",
         "sample_1_floydsteinberg.tiff",
         &DitherMethod::FloydSteinberg,
-    )?;
+    )
-    Ok(())
 }