fix 500 when reviewer is deleted with integration tests (#6856)

integrations/pull_review_test.go

@@ -0,0 +1,20 @@
+// 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 integrations
+
+import (
+	"net/http"
+	"testing"
+)
+
+func TestPullView_ReviewerMissed(t *testing.T) {
+	prepareTestEnv(t)
+	session := loginUser(t, "user1")
+
+	req := NewRequest(t, "GET", "/pulls")
+	session.MakeRequest(t, req, http.StatusOK)
+
+	req = NewRequest(t, "GET", "/user2/repo1/pulls/3")
+	session.MakeRequest(t, req, http.StatusOK)
+}