Add tests

Signed-off-by: Tushar Goel <tushar.goel.dav@gmail.com>

tests/contrib/test_utils.py

@@ -24,6 +24,8 @@
 # Visit https://github.com/package-url/packageurl-python for support and
 # download.
 
+import pytest
+
 from packageurl.contrib.django.utils import purl_to_lookups
 from packageurl.utils import get_golang_purl
 
@@ -70,3 +72,5 @@ def test_get_golang_purl():
         go_package="github.com/grpc-ecosystem/go-grpc-middleware v1.3.0"
     )
     assert "pkg:golang/github.com/grpc-ecosystem/go-grpc-middleware@v1.3.0" == str(golang_purl_2)
+    with pytest.raises(Exception):
+        get_golang_purl("github.com/envoyproxy/go-control-plane/envoy/config/listener@v3.1")