chore: add repo redirect unit test

models/fixtures/repo_redirect.yml

@@ -3,3 +3,9 @@
   owner_id: 2
   lower_name: oldrepo1
   redirect_repo_id: 1
+
+-
+  id: 2
+  owner_id: 17
+  lower_name: oldrepo24
+  redirect_repo_id: 24

services/redirect/repo_test.go

@@ -0,0 +1,55 @@
+// Copyright 2025 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+package redirect
+
+import (
+	"testing"
+
+	repo_model "forgejo.org/models/repo"
+	"forgejo.org/models/unittest"
+	user_model "forgejo.org/models/user"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestLookupRepoRedirect(t *testing.T) {
+	require.NoError(t, unittest.PrepareTestDatabase())
+
+	normalUser := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 5})
+	ownerUser := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 20})
+
+	testOk := func(t *testing.T, doer *user_model.User, ownerID int64, repoName string, expectedRedirectID int64) {
+		t.Helper()
+
+		redirectID, err := LookupRepoRedirect(t.Context(), doer, ownerID, repoName)
+		require.NoError(t, err)
+		assert.Equal(t, expectedRedirectID, redirectID)
+	}
+
+	testFail := func(t *testing.T, doer *user_model.User, ownerID int64, repoName string) {
+		t.Helper()
+
+		redirectID, err := LookupRepoRedirect(t.Context(), doer, ownerID, repoName)
+		require.ErrorIs(t, err, repo_model.ErrRedirectNotExist{OwnerID: ownerID, RepoName: repoName, MissingPermission: true})
+		assert.Zero(t, redirectID)
+	}
+
+	t.Run("Public repository", func(t *testing.T) {
+		ownerID := int64(2)
+		reponame := "oldrepo1"
+
+		testOk(t, nil, ownerID, reponame, 1)
+		testOk(t, normalUser, ownerID, reponame, 1)
+		testOk(t, ownerUser, ownerID, reponame, 1)
+	})
+
+	t.Run("Private repository", func(t *testing.T) {
+		ownerID := int64(17)
+		reponame := "oldrepo24"
+
+		testFail(t, nil, ownerID, reponame)
+		testFail(t, normalUser, ownerID, reponame)
+		testOk(t, ownerUser, ownerID, reponame, 24)
+	})
+}