diff --git a/tests/__init__.py b/tests/__init__.py
index e69de29..40a96af 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -0,0 +1 @@
+# -*- coding: utf-8 -*-
diff --git a/tests/conftest.py b/tests/conftest.py
index 23e220a..c06073c 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 """pytest configuration for the unit tests."""
 
 import os
diff --git a/tests/constants.py b/tests/constants.py
index 57d21aa..dd75304 100644
--- a/tests/constants.py
+++ b/tests/constants.py
@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 """Constants for unit tests."""
 
 
diff --git a/tests/test_identity.py b/tests/test_identity.py
index 329458d..87bca4b 100644
--- a/tests/test_identity.py
+++ b/tests/test_identity.py
@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 """Identity unit tests."""
 import os
 
diff --git a/tests/test_message.py b/tests/test_message.py
index 45fc4e4..39563a2 100644
--- a/tests/test_message.py
+++ b/tests/test_message.py
@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 """Message unit tests."""
 
 from . import constants
diff --git a/tests/test_pep.py b/tests/test_pep.py
index 79c052c..976c74f 100755
--- a/tests/test_pep.py
+++ b/tests/test_pep.py
@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 """Unit test for pEp package, not for subpackages or modules."""