Add unit test for remote asset processor

Signed-off-by: Adolfo García Veytia (Puerco) <[email protected]>

cmd/publish-release/cmd/github_test.go

@@ -0,0 +1,49 @@
+/*
+Copyright 2022 The Kubernetes 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 cmd
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestProcessRemoteAsset(t *testing.T) {
+	// Remove the fefault app creds temporarily
+	const gacVar = "GOOGLE_APPLICATION_CREDENTIALS"
+	prev := os.Getenv(gacVar)
+	defer t.Setenv(gacVar, prev)
+	t.Setenv(gacVar, "")
+
+	files := []string{}
+	defer func() {
+		for _, f := range files {
+			os.RemoveAll(f)
+		}
+	}()
+	path, err := processRemoteAsset("gs://kubernetes-release/release/v1.25.1/kubernetes.tar.gz.sha512")
+	require.NoError(t, err)
+	require.FileExists(t, path)
+	require.Equal(t, "kubernetes.tar.gz.sha512", filepath.Base(path))
+	files = append(files, path)
+
+	// Non existent object should fail
+	_, err = processRemoteAsset("gs://kubernetes-release/release/v1.25.1/0000000")
+	require.Error(t, err)
+}