refactor: flag to filter services instances

tsuru/client/services.go

@@ -177,9 +177,11 @@ func (s ServiceList) Run(ctx *cmd.Context) error {
 	if hasPool {
 		header = append(header, "Pool")
 	}
+	hasServiceWithInstances := false
 	table.Headers = tablecli.Row(header)
 	for _, s := range services {
 		for _, instance := range s.ServiceInstances {
+			hasServiceWithInstances = true
 			row := []string{s.Service, instance.Name}
 			if hasPool {
 				row = append(row, instance.Pool)
@@ -188,6 +190,9 @@ func (s ServiceList) Run(ctx *cmd.Context) error {
 			table.AddRow(r)
 		}
 	}
+	if !hasServiceWithInstances {
+		return nil
+	}
 
 	_, err = ctx.Stdout.Write(table.Bytes())
 	return err

tsuru/client/services_test.go

@@ -163,15 +163,14 @@ func (s *S) TestServiceListWithTags(c *check.C) {
 			ServiceInstances: []service.ServiceInstance{
 				{
 					Name: "mysql01",
-					Tags: []string{"production"},
 				},
 			},
 		},
 	})
 	c.Assert(err, check.IsNil)
 
 	ctx := cmd.Context{
-		Args:   []string{"--tag", "production"},
+		Args:   []string{},
 		Stdout: &stdout,
 		Stderr: &stderr,
 	}
@@ -183,19 +182,15 @@ func (s *S) TestServiceListWithTags(c *check.C) {
 			c.Assert(err, check.IsNil)
 
 			tags := req.Form["tag"]
-			c.Assert(tags, check.DeepEquals, []string{"production"})
+			c.Assert(tags, check.DeepEquals, []string{"tag1", "--tag"})
 
 			return strings.HasSuffix(req.URL.Path, "/services/instances")
 		},
 	}
-	serviceList := &ServiceList{
-		filter: serviceFilter{
-			tags: cmd.StringSliceFlag{"production"},
-		},
-	}
 	s.setupFakeTransport(&trans)
-
-	err = serviceList.Run(&ctx)
+	command := ServiceList{}
+	command.Flags().Parse(true, []string{"--tag", "tag1", "--tag", "tag2"})
+	err = command.Run(&ctx)
 	c.Assert(err, check.IsNil)
 
 	table := stdout.String()