diff --git a/tests/openwisp/test_backend.py b/tests/openwisp/test_backend.py
index 41768c395..f421d8ebc 100644
--- a/tests/openwisp/test_backend.py
+++ b/tests/openwisp/test_backend.py
@@ -15,7 +15,7 @@ class TestBackend(unittest.TestCase, _TabsMixin):
     """
     config = {
         "general": {
-            "hostname": "openwisp_test"
+            "hostname": "openwisp-test"
         },
         "interfaces": [
             {
@@ -118,7 +118,7 @@ class TestBackend(unittest.TestCase, _TabsMixin):
     def test_uci(self):
         o = OpenWisp({
             "general": {
-                "hostname": "openwisp_test"
+                "hostname": "openwisp-test"
             }
         })
         tar = tarfile.open(fileobj=o.generate(), mode='r')
@@ -127,7 +127,7 @@ def test_uci(self):
         expected = self._tabs("""package system
 
 config system
-    option hostname 'openwisp_test'
+    option hostname 'openwisp-test'
     option timezone 'UTC'
 """)
         self.assertEqual(contents, expected)
diff --git a/tests/openwrt/test_system.py b/tests/openwrt/test_system.py
index dfcfa657a..a996a89af 100644
--- a/tests/openwrt/test_system.py
+++ b/tests/openwrt/test_system.py
@@ -12,7 +12,7 @@ class TestSystemRenderer(unittest.TestCase, _TabsMixin):
     def test_system(self):
         o = OpenWrt({
             "general": {
-                "hostname": "test_system",
+                "hostname": "test-system",
                 "timezone": "Europe/Rome",
                 "custom_setting": True,
                 "empty_setting1": None,
@@ -23,7 +23,7 @@ def test_system(self):
 
 config system
     option custom_setting '1'
-    option hostname 'test_system'
+    option hostname 'test-system'
     option timezone 'CET-1CEST,M3.5.0,M10.5.0/3'
 """)
         self.assertEqual(o.render(), expected)
diff --git a/tests/test_bin.py b/tests/test_bin.py
index 8dfd4ba15..02df73522 100644
--- a/tests/test_bin.py
+++ b/tests/test_bin.py
@@ -35,7 +35,7 @@ def test_empty_netjson(self):
 
     def test_templates(self):
         config = json.dumps({
-            'general': {'hostname': 'template_test'}
+            'general': {'hostname': 'template-test'}
         })
         template1 = json.dumps({
             'interfaces': [
@@ -68,7 +68,7 @@ def test_templates(self):
         command = """netjsonconfig --config '{0}' -b openwrt -m render --templates '{1}' '{2}'"""
         command = command.format(config, template1, template2)
         output = subprocess.check_output(command, shell=True).decode()
-        self.assertIn("hostname 'template_test'", output)
+        self.assertIn("hostname 'template-test'", output)
         self.assertIn("interface 'eth0'", output)
         self.assertIn("interface 'wlan0'", output)
 
@@ -101,7 +101,7 @@ def test_arg_exception(self):
 
     def test_valid_arg(self):
         config = json.dumps({
-            'general': {'hostname': 'template_test'},
+            'general': {'hostname': 'template-test'},
             'files': [
                 {
                     'path': '/etc/test.txt',