fix: misc fixes in pub/gpg/tests (#38809)

- The pub registry reported the oldest version as `latest`, because the
descriptor slice is sorted ascending but the first element was used.
- Verifying a GPG or SSH key flashed success and redirected after
already writing an error response, so a failure was reported as a
success with an empty key id.
- Test packages sharing redis could tear down each other's server.
`PrepareTestRedis` started its own on the well-known port, so a package
running in parallel borrowed it and lost it when the owner's cleanup
fired. It now listens on a socket of its own.

modules/globallock/globallock_test.go

@@ -7,6 +7,9 @@ import (
 	"context"
 	"sync"
 	"testing"
+	"time"
+
+	"gitea.dev/modules/test"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -14,6 +17,7 @@ import (
 
 func TestLockAndDo(t *testing.T) {
 	t.Run("redis", func(t *testing.T) {
+		defer test.MockVariableValue(&redisLockExpiry, 5*time.Second)() // Close waits for the extend goroutine's next tick
 		locker := newTestRedisLocker(t)
 		defaultLocker.Store(new(locker))
 		testLockAndDo(t)

modules/globallock/locker_test.go

@@ -5,13 +5,11 @@ package globallock
 
 import (
 	"context"
-	"os"
 	"sync"
 	"testing"
 	"time"
 
 	"gitea.dev/modules/test"
-	"gitea.dev/modules/util"
 
 	"github.com/go-redsync/redsync/v4"
 	"github.com/stretchr/testify/assert"
@@ -20,14 +18,7 @@ import (
 
 func newTestRedisLocker(t *testing.T) Locker {
 	t.Helper()
-	redisURL := util.IfZero(os.Getenv("TEST_REDIS_URL"), "redis://127.0.0.1:6379/0")
-	rl := NewRedisLocker(redisURL).(*redisLocker)
-	err := rl.conn.Ping(t.Context()).Err()
-	if err != nil && test.AllowSkipExternalService() {
-		t.Skip("no redis server for testing, skipped")
-	}
-	require.NoError(t, err, "redis error for testing: %v", err)
-	return rl
+	return NewRedisLocker(test.PrepareTestRedis(t))
 }
 
 func TestLocker(t *testing.T) {