fix tests

Author: helenfufu

api/sys_plugins.go

@@ -242,6 +242,8 @@ func (c *Sys) RegisterPluginWithContext(ctx context.Context, i *RegisterPluginIn
 	resp, err := c.c.rawRequestWithContext(ctx, req)
 	if err == nil {
 		defer resp.Body.Close()
+	} else {
+		return nil, err
 	}
 
 	var registerResp RegisterPluginResponse

command/util.go

@@ -4,6 +4,7 @@
 package command
 
 import (
+	"bytes"
 	"fmt"
 	"io"
 	"net/http"
@@ -193,6 +194,7 @@ func (r *recordingRoundTripper) RoundTrip(req *http.Request) (*http.Response, er
 	r.body = body
 	return &http.Response{
 		StatusCode: 200,
+		Body:       io.NopCloser(bytes.NewReader([]byte(`{"warnings": []}`))),
 	}, nil
 }