You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: cache_test.go
    path of file: ./repos/cockroach/pkg/server/systemconfigwatcher
    
    the code of the file until where you have to start completion: // Copyright 2022 The Cockroach Authors.
//
// Use of this software is governed by
    
func TestNewWithAdditionalProvider(t *testing.T) {
	defer leaktest.AfterTest(t)()
	defer log.Scope(t).Close(t)

	ctx := context.Background()
	s, sqlDB, kvDB := serverutils.StartServer(t, base.TestServerArgs{
		DefaultTestTenant: base.TestIsSpecificToStorageLayerAndNeedsASystemTenant,
	})
	defer s.Stopper().Stop(ctx)
	tdb := sqlutils.MakeSQLRunner(sqlDB)
	tdb.Exec(t, `SET CLUSTER SETTING kv.closed_timestamp.target_duration = '20ms'`)
	tdb.Exec(t, `SET CLUSTER SETTING kv.closed_timestamp.side_transport_interval = '20ms'`)
	tdb.Exec(t, `SET CLUSTER SETTING kv.rangefeed.closed_timestamp_refresh_interval = '20ms'`)
	fakeTenant := roachpb.MustMakeTenantID(10)
	codec := keys.MakeSQLCodec(fakeTenant)
	fp := &fakeProvider{
		ch: make(chan struct{}, 1),
	}
	fp.setSystemConfig(config.NewSystemConfig(zonepb.DefaultZoneConfigRef()))
	cache := systemconfigwatcher.NewWithAdditionalProvider(
		codec, s.Clock(), s.RangeFeedFactory().(*rangefeed.Factory),
		zonepb.DefaultZoneConfigRef(), fp,
	)
	mkKV := func(key, value string) roachpb.KeyValue {
		return roachpb.KeyValue{
			Key:   []byte(key),
			Value: func() (v roachpb.Value) { v.SetString(value); return v }(),
		}
	}
	setAdditional := func(kvs ...roachpb.KeyValue) {
		additional := config.SystemConfig{}
		additional.Values = kvs
		fp.setSystemConfig(&additional)
	}
	kvA := mkKV("a", "value")
	setAdditional(kvA)
	fp.ch <- struct{}{}

	ch, _ := cache.RegisterSystemConfigChannel()
	require.NoError(t, cache.Start(ctx, s.Stopper()))
	getValues := func() []roachpb.KeyValue {
		return cache.GetSystemConfig().SystemConfigEntries.Values
	}

	<-ch // we'll get notified upon initial scan, which should be empty
	require.Equal(t, []roachpb.KeyValue{kvA}, getValues())

	// Update the kv-pair and make sure it propagates
	kvB := mkKV("b", "value")
	setAdditional(kvB)
	fp.ch <- struct{}{}
	<-ch
	require.Equal(t, []roachpb.KeyValue{kvB}, getValues())

	mkTenantKey := func(key string) roachpb.Key {
		return append(codec.TablePrefix(keys.ZonesTableID), key...)
	}
	// Write a value and make sure that it shows up.
	tenantA := mkTenantKey("a")
	require.NoError(t, kvDB.Put(ctx, tenantA, "value"))
	<-ch
	require.Len(t, getValues(), 2)
	require.Equal(t, kvB, getValues()[0])
	require.Equal(t, tenantA, getValues()[1].Key)

	// Update the additional value.
	kvC := mkKV("c", "value")
	setAdditional(kvA, kvC)
	fp.ch <- struct{}{}
	<-ch
	require.Len(t, getValues(), 3)
	require.Equal(t, kvA, getValues()[0])
	require.Equal(t, kvC, getValues()[1])
	require.Equal(t, tenantA, getValues()[2].Key)
}