diff --git a/src/tests/test_api.py b/src/tests/test_api.py
index e172bc7..cceefb7 100644
--- a/src/tests/test_api.py
+++ b/src/tests/test_api.py
@@ -17,6 +17,7 @@
 
 from urllib.parse import urlencode
 import json
+import pytest
 
 __author__ = 'Michael Mader'
 __date__ = "2023-03-12"
@@ -63,3 +64,26 @@ def test_multiply(client):
 def test_division(client):
     result = call(client, '/div', {'x': 35, 'y': 7})
     assert result['result'] == 5
+
+# type tests
+def test_type_inc(client):
+    result = call(client, '/inc', {'x': 'a'})
+    assert result["error"] == "Type error"
+
+def test_type_add(client):
+    result = call(client, '/add', {'x': 'a', 'y': 1})
+    assert result["error"] == "Type error"
+    result = call(client, '/add', {'x': 1, 'y': 'a'})
+    assert result["error"] == "Type error"
+
+def test_type_mul(client):
+    result = call(client, '/mul', {'x': 'a', 'y': 1})
+    assert result["error"] == "Type error"
+    result = call(client, '/mul', {'x': 1, 'y': 'a'})
+    assert result["error"] == "Type error"
+
+def test_type_div(client):
+    result = call(client, '/div', {'x': 'a', 'y': 1})
+    assert result["error"] == "Type error"
+    result = call(client, '/div', {'x': 1, 'y': 'a'})
+    assert result["error"] == "Type error"
\ No newline at end of file