remove fake instance manager

Author: ryantxu

pkg/plugin/datasource_test.go

@@ -5,7 +5,6 @@ import (
 	"testing"
 
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
-	"github.com/grafana/grafana-plugin-sdk-go/backend/instancemgmt"
 	"github.com/grafana/mqtt-datasource/pkg/mqtt"
 	"github.com/grafana/mqtt-datasource/pkg/plugin"
 	"github.com/stretchr/testify/require"
@@ -43,21 +42,6 @@ func TestCheckHealthHandler(t *testing.T) {
 	})
 }
 
-type fakeInstanceManager struct {
-	client *fakeMQTTClient
-	err    error
-}
-
-func (im *fakeInstanceManager) Get(pc backend.PluginContext) (instancemgmt.Instance, error) {
-	return &plugin.MQTTDatasource{
-		Client: im.client,
-	}, im.err
-}
-
-func (im *fakeInstanceManager) Do(pc backend.PluginContext, fn instancemgmt.InstanceCallbackFunc) error {
-	return nil
-}
-
 type fakeMQTTClient struct {
 	connected  bool
 	subscribed bool