diff --git a/gunicorn/http/errors.py b/gunicorn/http/errors.py
index 340f0473c..1e3c5e752 100644
--- a/gunicorn/http/errors.py
+++ b/gunicorn/http/errors.py
@@ -53,7 +53,7 @@ def __init__(self, version):
         self.version = version
 
     def __str__(self):
-        return "Invalid HTTP Version: %r" % self.version
+        return "Invalid HTTP Version: %r" % (self.version,)
 
 
 class InvalidHeader(ParseException):
diff --git a/tests/test_http.py b/tests/test_http.py
index 0eb694601..f0ddc3bb2 100644
--- a/tests/test_http.py
+++ b/tests/test_http.py
@@ -9,7 +9,7 @@
 from gunicorn.http.body import Body, LengthReader, EOFReader
 from gunicorn.http.wsgi import Response
 from gunicorn.http.unreader import Unreader, IterUnreader, SocketUnreader
-from gunicorn.http.errors import InvalidHeader, InvalidHeaderName
+from gunicorn.http.errors import InvalidHeader, InvalidHeaderName, InvalidHTTPVersion
 from gunicorn.http.message import TOKEN_RE
 
 
@@ -238,3 +238,8 @@ def test_eof_reader_read_invalid_size():
         reader.read([100])
     with pytest.raises(ValueError):
         reader.read(-100)
+
+
+def test_invalid_http_version_error():
+    assert str(InvalidHTTPVersion('foo')) == "Invalid HTTP Version: 'foo'"
+    assert str(InvalidHTTPVersion((2, 1))) == 'Invalid HTTP Version: (2, 1)'