diff --git a/miplearn/solvers/tests/__init__.py b/miplearn/solvers/tests/__init__.py
index b9540c4..a93016d 100644
--- a/miplearn/solvers/tests/__init__.py
+++ b/miplearn/solvers/tests/__init__.py
@@ -4,6 +4,8 @@
 
 from typing import Any, List
 
+import numpy as np
+
 from miplearn.features import VariableFeatures, ConstraintFeatures
 from miplearn.solvers.internal import InternalSolver
 
@@ -282,4 +284,8 @@ def run_lazy_cb_tests(solver: InternalSolver) -> None:
 
 
 def assert_equals(left: Any, right: Any) -> None:
+    if isinstance(left, np.ndarray):
+        left = left.tolist()
+    if isinstance(right, np.ndarray):
+        right = right.tolist()
     assert left == right, f"left:\n{left}\nright:\n{right}"
diff --git a/tests/test_features.py b/tests/test_features.py
index 5d2cf2d..aa23fb4 100644
--- a/tests/test_features.py
+++ b/tests/test_features.py
@@ -13,6 +13,7 @@ from miplearn.solvers.tests import (
     assert_equals,
     _round,
 )
+import numpy as np
 
 inf = float("inf")
 
@@ -134,3 +135,16 @@ def test_constraint_getindex() -> None:
             ],
         ),
     )
+
+
+def test_assert_equals() -> None:
+    assert_equals("hello", "hello")
+    assert_equals([1.0, 2.0], [1.0, 2.0])
+    assert_equals(
+        np.array([1.0, 2.0]),
+        np.array([1.0, 2.0]),
+    )
+    assert_equals(
+        np.array([[1.0, 2.0], [3.0, 4.0]]),
+        np.array([[1.0, 2.0], [3.0, 4.0]]),
+    )