diff --git a/tests/test_requests.py b/tests/test_requests.py
index a458bf9d..cc621a20 100755
--- a/tests/test_requests.py
+++ b/tests/test_requests.py
@@ -1039,23 +1039,22 @@ class TestRequests:
         r = requests.Response()
         r.raw = io.BytesIO(b'the content')
         r.encoding = 'ascii'
+
         chunks = r.iter_content(decode_unicode=True)
         assert all(isinstance(chunk, str) for chunk in chunks)
 
+    @pytest.mark.parametrize(
+        'encoding, exception', (
+            (None, TypeError),
+            ('invalid encoding', LookupError),
+        ))
+    def test_decode_unicode_encoding(self, encoding, exception):
         # raise an exception if encoding isn't set
         r = requests.Response()
         r.raw = io.BytesIO(b'the content')
-        r.encoding = None
+        r.encoding = encoding
 
-        with pytest.raises(TypeError):
-            chunks = r.iter_content(decode_unicode=True)
-
-        # raises an exception if the encoding is garbage
-        r = requests.Response()
-        r.raw = io.BytesIO(b'the content')
-        r.encoding = 'invalid encoding'
-
-        with pytest.raises(LookupError):
+        with pytest.raises(exception):
             chunks = r.iter_content(decode_unicode=True)
 
     def test_response_reason_unicode(self):