Add plugin hook tester

plugins/hooktester.go

@@ -0,0 +1,19 @@
+package plugins
+
+
+// type PluginLoader struct{
+// 	Plugins []*plugin.Plugin
+// 	Subcommands map[string]Subcommand
+// 	Flags []*flag.FlagSet
+// 	LookupCache map[string][]interface{}
+// }
+
+func HookTester(name string, fn interface{}) func() {
+  oldDefault := DefaultPluginLoader
+  DefaultPluginLoader = &PluginLoader{
+    LookupCache: map[string][]interface{}{
+      name: []interface{}{fn},
+    },
+  }
+  return func() { DefaultPluginLoader = oldDefault }
+}