diff --git a/pkg/plugin/cache/cache_test.go b/pkg/plugin/cache/cache_test.go
new file mode 100644
index 000000000..43959a374
--- /dev/null
+++ b/pkg/plugin/cache/cache_test.go
@@ -0,0 +1,53 @@
+/*
+Copyright The Helm Authors.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cache
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestKey(t *testing.T) {
+	cases := []struct {
+		repo          string
+		expected      string
+		expectedError bool
+	}{
+		{
+			repo:     "git@host:user/repo.git",
+			expected: "git-host-user-repo.git",
+		},
+		{
+			repo:     "https://host/user/repo.git",
+			expected: "https-host-user-repo.git",
+		},
+		{
+			repo:          "https://host:user/repo.git",
+			expectedError: true,
+		},
+	}
+	for _, c := range cases {
+		t.Run(c.repo, func(t *testing.T) {
+			got, err := Key(c.repo)
+			if (err != nil) != c.expectedError {
+				t.Errorf("got unexpected error: %v", err)
+			}
+			if !reflect.DeepEqual(c.expected, got) {
+				t.Errorf("expected: %v, got: %v", c.expected, got)
+			}
+		})
+	}
+}