Improve memory store tests reliability (#479)

* remove unnecessary GIT_BRANCH export

* go mod tidy

* fix tests naming, improve coverage

* make flaky TestMemData_FlagListBlocked reliable

backend/_example/memory_store/server/rpc.go

@@ -129,7 +129,7 @@ func (s *RPC) listFlagsHndl(id uint64, params json.RawMessage) (rr jrpc.Response
 	return jrpc.EncodeResponse(id, flags, err)
 }
 
-// deleteHndl remove comment(s)
+// deleteHndl delete post(s), user, comment, or everything
 func (s *RPC) deleteHndl(id uint64, params json.RawMessage) (rr jrpc.Response) {
 	req := engine.DeleteRequest{}
 	if err := json.Unmarshal(params, &req); err != nil {

backend/_example/memory_store/server/rpc_test.go

@@ -14,12 +14,13 @@ import (
 	"time"
 
 	"github.com/go-pkgz/jrpc"
+	log "github.com/go-pkgz/lgr"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-
 	"github.com/umputun/remark/backend/app/store"
 	"github.com/umputun/remark/backend/app/store/admin"
 	"github.com/umputun/remark/backend/app/store/engine"
+
 	"github.com/umputun/remark/memory_store/accessor"
 )
 
@@ -344,9 +345,10 @@ func prepTestStore(t *testing.T) (s *RPC, port int, teardown func()) {
 	adm.Set("test-site-disabled", admRecDisabled)
 
 	go func() {
-		t.Log(s.Run(port))
+		log.Printf("%v", s.Run(port))
 	}()
-	time.Sleep(time.Millisecond * 10)
+
+	time.Sleep(time.Millisecond * 50) // wait for server to start
 
 	return s, port, func() {
 		require.NoError(t, s.Shutdown())