diff --git a/scilpy/connectivity/tests/test_connectivity.py b/scilpy/connectivity/tests/test_connectivity.py
index 0931162a1..384084e7d 100644
--- a/scilpy/connectivity/tests/test_connectivity.py
+++ b/scilpy/connectivity/tests/test_connectivity.py
@@ -23,8 +23,8 @@ def test_compute_triu_connectivity_from_labels():
         tractogram, labels)
     assert np.array_equal(output.shape, [8, 8])
     expected_out = np.zeros((8, 8))
-    expected_out[1, 3] = 1
-    expected_out[4, 6] = 2
+    expected_out[1, 3] = 1  # This is labels (4, 6)
+    expected_out[4, 6] = 2  # This is labels (7, 9)
     assert np.array_equal(output, expected_out)
 
 
diff --git a/scilpy/connectivity/tests/test_matrix_tools.py b/scilpy/connectivity/tests/test_matrix_tools.py
index d3b0595d2..02b6b265d 100644
--- a/scilpy/connectivity/tests/test_matrix_tools.py
+++ b/scilpy/connectivity/tests/test_matrix_tools.py
@@ -1,4 +1,7 @@
 # -*- coding: utf-8 -*-
+import numpy as np
+
+from scilpy.connectivity.matrix_tools import apply_reordering
 
 
 def test_compute_olo():
@@ -10,8 +13,24 @@ def test_apply_olo():
 
 
 def test_apply_reordering():
-    pass
-
+    conn_matrix = np.asarray([[1, 2, 3, 4],
+                              [5, 6, 7, 8],
+                              [9, 10, 11, 12],
+                              [13, 14, 15, 16]])
+    output = apply_reordering(conn_matrix, [[0, 1, 3, 2],
+                                            [1, 2, 3, 0]])
+    # First changing rows 2 and 3
+    expected_out = np.asarray([[1, 2, 3, 4],
+                              [5, 6, 7, 8],
+                              [13, 14, 15, 16],
+                              [9, 10, 11, 12]])
+    # Permuting columns
+    expected_out = np.asarray([[2, 3, 4, 1],
+                              [6, 7, 8, 5],
+                              [14, 15, 16, 13],
+                              [10, 11, 12, 9]])
+    assert np.array_equal(output, expected_out)
+    
 
 def test_evaluate_graph_measures():
     pass