docs(utils): add description for testOpts struct

Signed-off-by: vadasambar <[email protected]>

cluster-autoscaler/utils/drain/drain_test.go

@@ -33,6 +33,7 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+// testOpts represents parameters required for a single unit test
 type testOpts struct {
 	description         string
 	pods                []*apiv1.Pod