Move pull request api convert to convert package (#9664)

* Move pull request api convert to convert package

* Rename ToPullRequest to ToAPIPullRequest

modules/convert/pull_test.go

@@ -0,0 +1,23 @@
+// Copyright 2020 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 convert
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/models"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPullRequest_APIFormat(t *testing.T) {
+	assert.NoError(t, models.PrepareTestDatabase())
+	pr := models.AssertExistsAndLoadBean(t, &models.PullRequest{ID: 1}).(*models.PullRequest)
+	assert.NoError(t, pr.LoadAttributes())
+	assert.NoError(t, pr.LoadIssue())
+	apiPullRequest := ToAPIPullRequest(pr)
+	assert.NotNil(t, apiPullRequest)
+	assert.Nil(t, apiPullRequest.Head)
+}