*: make TestConfig stable (#7463)

close #7440

Signed-off-by: Ryan Leung <rleungx@gmail.com>

Co-authored-by: ti-chi-bot[bot] <108142056+ti-chi-bot[bot]@users.noreply.github.com>

pkg/dashboard/adapter/manager.go

@@ -19,6 +19,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/pingcap/failpoint"
 	"github.com/pingcap/kvproto/pkg/pdpb"
 	"github.com/pingcap/log"
 	"github.com/pingcap/tidb-dashboard/pkg/apiserver"
@@ -75,6 +76,10 @@ func (m *Manager) Stop() {
 func (m *Manager) serviceLoop() {
 	defer logutil.LogPanic()
 	defer m.wg.Done()
+	// TODO: After we fix the atomic problem of config, we can remove this failpoint.
+	failpoint.Inject("skipDashboardLoop", func() {
+		failpoint.Return()
+	})
 
 	ticker := time.NewTicker(CheckInterval)
 	defer ticker.Stop()

tests/pdctl/config/config_test.go

@@ -24,6 +24,7 @@ import (
 	"time"
 
 	"github.com/coreos/go-semver/semver"
+	"github.com/pingcap/failpoint"
 	"github.com/pingcap/kvproto/pkg/metapb"
 	"github.com/stretchr/testify/require"
 	"github.com/stretchr/testify/suite"
@@ -60,8 +61,10 @@ func TestConfigTestSuite(t *testing.T) {
 }
 
 func (suite *configTestSuite) TestConfig() {
+	suite.NoError(failpoint.Enable("github.com/tikv/pd/pkg/dashboard/adapter/skipDashboardLoop", `return(true)`))
 	env := tests.NewSchedulingTestEnvironment(suite.T())
 	env.RunTestInTwoModes(suite.checkConfig)
+	suite.NoError(failpoint.Disable("github.com/tikv/pd/pkg/dashboard/adapter/skipDashboardLoop"))
 }
 
 func (suite *configTestSuite) checkConfig(cluster *tests.TestCluster) {