diff --git a/tests/test_auth.py b/tests/test_auth.py
index c5c082b..45e6cff 100644
--- a/tests/test_auth.py
+++ b/tests/test_auth.py
@@ -128,7 +128,11 @@ class TestAuth(unittest.TestCase):
     def test_header(self):
         """Test header data."""
         self.auth.token = "bar"
-        expected_header = {"TOKEN_AUTH": "bar", "user-agent": const.DEFAULT_USER_AGENT}
+        expected_header = {
+            "TOKEN_AUTH": "bar",
+            "user-agent": const.DEFAULT_USER_AGENT,
+            "content-type": "application/json",
+        }
         self.assertDictEqual(self.auth.header, expected_header)
 
     def test_header_no_token(self):