diff --git a/benches/dpa.rs b/benches/dpa.rs
index f5620fe..2fa2b10 100644
--- a/benches/dpa.rs
+++ b/benches/dpa.rs
@@ -1,12 +1,12 @@
 use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion};
 use muscat::distinguishers::dpa::{dpa, Dpa, DpaProcessor};
 use muscat::leakage::sbox;
-use ndarray::{Array1, Array2};
+use ndarray::{Array1, Array2, ArrayView1};
 use ndarray_rand::rand::{rngs::StdRng, SeedableRng};
 use ndarray_rand::rand_distr::Uniform;
 use ndarray_rand::RandomExt;
 
-fn selection_function(metadata: Array1<u8>, guess: usize) -> bool {
+fn selection_function(metadata: ArrayView1<u8>, guess: usize) -> bool {
     usize::from(sbox(metadata[1] ^ guess as u8)) & 1 == 1
 }
 
@@ -14,7 +14,7 @@ fn dpa_sequential(traces: &Array2<f32>, plaintexts: &Array2<u8>) -> Dpa {
     let mut dpa = DpaProcessor::new(traces.shape()[1], 256, selection_function);
 
     for i in 0..traces.shape()[0] {
-        dpa.update(traces.row(i), plaintexts.row(i).to_owned());
+        dpa.update(traces.row(i), plaintexts.row(i));
     }
 
     dpa.finalize()
@@ -26,8 +26,7 @@ fn dpa_parallel(traces: &Array2<f32>, plaintexts: &Array2<u8>) -> Dpa {
         plaintexts
             .rows()
             .into_iter()
-            .map(|x| x.to_owned())
-            .collect::<Array1<Array1<u8>>>()
+            .collect::<Array1<ArrayView1<u8>>>()
             .view(),
         256,
         selection_function,
diff --git a/src/distinguishers/cpa.rs b/src/distinguishers/cpa.rs
index fb57f9a..92752a9 100644
--- a/src/distinguishers/cpa.rs
+++ b/src/distinguishers/cpa.rs
@@ -282,3 +282,36 @@ where
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::{cpa, CpaProcessor};
+    use ndarray::array;
+
+    #[test]
+    fn test_cpa_helper() {
+        let traces = array![
+            [77usize, 137, 51, 91],
+            [72, 61, 91, 83],
+            [39, 49, 52, 23],
+            [26, 114, 63, 45],
+            [30, 8, 97, 91],
+            [13, 68, 7, 45],
+            [17, 181, 60, 34],
+            [43, 88, 76, 78],
+            [0, 36, 35, 0],
+            [93, 191, 49, 26],
+        ];
+        let plaintexts = array![[1usize], [3], [1], [2], [3], [2], [2], [1], [3], [1]];
+
+        let leakage_model = |value, guess| value ^ guess;
+        let mut processor = CpaProcessor::new(traces.shape()[1], 256, 0, leakage_model);
+        for i in 0..traces.shape()[0] {
+            processor.update(traces.row(i), plaintexts.row(i));
+        }
+        assert_eq!(
+            processor.finalize().corr(),
+            cpa(traces.view(), plaintexts.view(), 256, 0, leakage_model, 2).corr()
+        );
+    }
+}
diff --git a/src/distinguishers/cpa_normal.rs b/src/distinguishers/cpa_normal.rs
index b77728c..0b08588 100644
--- a/src/distinguishers/cpa_normal.rs
+++ b/src/distinguishers/cpa_normal.rs
@@ -245,3 +245,48 @@ where
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use std::iter::zip;
+
+    use super::{cpa, CpaProcessor};
+    use ndarray::{array, ArrayView1, Axis};
+
+    #[test]
+    fn test_cpa_helper() {
+        let traces = array![
+            [77usize, 137, 51, 91],
+            [72, 61, 91, 83],
+            [39, 49, 52, 23],
+            [26, 114, 63, 45],
+            [30, 8, 97, 91],
+            [13, 68, 7, 45],
+            [17, 181, 60, 34],
+            [43, 88, 76, 78],
+            [0, 36, 35, 0],
+            [93, 191, 49, 26],
+        ];
+        let plaintexts = array![[1usize], [3], [1], [2], [3], [2], [2], [1], [3], [1]];
+
+        let leakage_model = |plaintext: ArrayView1<usize>, guess| plaintext[0] ^ guess;
+        let mut processor = CpaProcessor::new(traces.shape()[1], 1, 256, leakage_model);
+        for (trace, plaintext) in zip(
+            traces.axis_chunks_iter(Axis(0), 1),
+            plaintexts.axis_chunks_iter(Axis(0), 1),
+        ) {
+            processor.update(trace.map(|&x| x as f32).view(), plaintext.view());
+        }
+        assert_eq!(
+            processor.finalize().corr(),
+            cpa(
+                traces.map(|&x| x as f32).view(),
+                plaintexts.view(),
+                256,
+                leakage_model,
+                2
+            )
+            .corr()
+        );
+    }
+}
diff --git a/src/distinguishers/dpa.rs b/src/distinguishers/dpa.rs
index c0f899e..1aa305c 100644
--- a/src/distinguishers/dpa.rs
+++ b/src/distinguishers/dpa.rs
@@ -245,3 +245,48 @@ where
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::{dpa, DpaProcessor};
+    use ndarray::{array, Array1, ArrayView1};
+
+    #[test]
+    fn test_dpa_helper() {
+        let traces = array![
+            [77usize, 137, 51, 91],
+            [72, 61, 91, 83],
+            [39, 49, 52, 23],
+            [26, 114, 63, 45],
+            [30, 8, 97, 91],
+            [13, 68, 7, 45],
+            [17, 181, 60, 34],
+            [43, 88, 76, 78],
+            [0, 36, 35, 0],
+            [93, 191, 49, 26],
+        ];
+        let plaintexts = array![[1], [3], [1], [2], [3], [2], [2], [1], [3], [1]];
+
+        let selection_function =
+            |plaintext: ArrayView1<u8>, guess| (plaintext[0] as usize ^ guess) & 1 == 1;
+        let mut processor = DpaProcessor::new(traces.shape()[1], 256, selection_function);
+        for i in 0..traces.shape()[0] {
+            processor.update(traces.row(i).map(|&x| x as f32).view(), plaintexts.row(i));
+        }
+        assert_eq!(
+            processor.finalize().differential_curves(),
+            dpa(
+                traces.view().map(|&x| x as f32).view(),
+                plaintexts
+                    .rows()
+                    .into_iter()
+                    .collect::<Array1<ArrayView1<u8>>>()
+                    .view(),
+                256,
+                selection_function,
+                2
+            )
+            .differential_curves()
+        );
+    }
+}
diff --git a/src/leakage_detection.rs b/src/leakage_detection.rs
index 8773dac..be54398 100644
--- a/src/leakage_detection.rs
+++ b/src/leakage_detection.rs
@@ -63,7 +63,7 @@ where
             || SnrProcessor::new(traces.shape()[1], classes),
             |mut snr, (batch_idx, trace_batch)| {
                 for i in 0..trace_batch.shape()[0] {
-                    snr.process(trace_batch.row(i), get_class(batch_idx + i));
+                    snr.process(trace_batch.row(i), get_class(batch_idx * batch_size + i));
                 }
                 snr
             },
@@ -317,12 +317,34 @@ impl Add for TTestProcessor {
 
 #[cfg(test)]
 mod tests {
-    use super::{ttest, TTestProcessor};
+    use super::{snr, ttest, SnrProcessor, TTestProcessor};
     use ndarray::array;
 
+    #[test]
+    fn test_snr_helper() {
+        let traces = array![
+            [77, 137, 51, 91],
+            [72, 61, 91, 83],
+            [39, 49, 52, 23],
+            [26, 114, 63, 45],
+            [30, 8, 97, 91],
+            [13, 68, 7, 45],
+            [17, 181, 60, 34],
+            [43, 88, 76, 78],
+            [0, 36, 35, 0],
+            [93, 191, 49, 26],
+        ];
+        let classes = [1, 3, 1, 2, 3, 2, 2, 1, 3, 1];
+
+        let mut processor = SnrProcessor::new(traces.shape()[1], 256);
+        for (trace, class) in std::iter::zip(traces.rows(), classes.iter()) {
+            processor.process(trace, *class);
+        }
+        assert_eq!(processor.snr(), snr(traces.view(), 256, |i| classes[i], 2));
+    }
+
     #[test]
     fn test_ttest() {
-        let mut processor = TTestProcessor::new(4);
         let traces = [
             array![77, 137, 51, 91],
             array![72, 61, 91, 83],
@@ -335,9 +357,12 @@ mod tests {
             array![0, 36, 35, 0],
             array![93, 191, 49, 26],
         ];
+
+        let mut processor = TTestProcessor::new(4);
         for (i, trace) in traces.iter().enumerate() {
             processor.process(trace.view(), i % 3 == 0);
         }
+
         assert_eq!(
             processor.ttest(),
             array![
@@ -351,7 +376,6 @@ mod tests {
 
     #[test]
     fn test_ttest_helper() {
-        let mut processor = TTestProcessor::new(4);
         let traces = array![
             [77, 137, 51, 91],
             [72, 61, 91, 83],
@@ -366,6 +390,8 @@ mod tests {
         ];
         let trace_classes =
             array![true, false, false, true, false, false, true, false, false, true];
+
+        let mut processor = TTestProcessor::new(4);
         for (i, trace) in traces.rows().into_iter().enumerate() {
             processor.process(trace, trace_classes[i]);
         }