Move milestone to models/issues/ (#19278)

* Move milestone to models/issues/

* Fix lint

* Fix test

* Fix lint

* Fix lint

services/issue/milestone_test.go

@@ -0,0 +1,35 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package issue
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/models"
+	issues_model "code.gitea.io/gitea/models/issues"
+	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestChangeMilestoneAssign(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+	issue := unittest.AssertExistsAndLoadBean(t, &models.Issue{RepoID: 1}).(*models.Issue)
+	doer := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2}).(*user_model.User)
+	assert.NotNil(t, issue)
+	assert.NotNil(t, doer)
+
+	oldMilestoneID := issue.MilestoneID
+	issue.MilestoneID = 2
+	assert.NoError(t, ChangeMilestoneAssign(issue, doer, oldMilestoneID))
+	unittest.AssertExistsAndLoadBean(t, &models.Comment{
+		IssueID:        issue.ID,
+		Type:           models.CommentTypeMilestone,
+		MilestoneID:    issue.MilestoneID,
+		OldMilestoneID: oldMilestoneID,
+	})
+	unittest.CheckConsistencyFor(t, &issues_model.Milestone{}, &models.Issue{})
+}