test: Fix kvstore test

abci/client/client.go

@@ -128,6 +128,18 @@ func (r *ReqRes) SetInvoked() {
 	r.mtx.Unlock()
 }
 
+// GetCallback returns the configured callback of the ReqRes object which may be
+// nil. Note, it is not safe to concurrently call this in cases where it is
+// marked done and SetCallback is called before calling GetCallback as that
+// will invoke the callback twice and create a potential race condition.
+//
+// ref: https://github.com/tendermint/tendermint/issues/5439
+func (r *ReqRes) GetCallback() func(*types.Response) {
+	r.mtx.Lock()
+	defer r.mtx.Unlock()
+	return r.cb
+}
+
 func waitGroup1() (wg *sync.WaitGroup) {
 	wg = &sync.WaitGroup{}
 	wg.Add(1)

abci/example/kvstore/kvstore_test.go

@@ -33,16 +33,15 @@ func TestKVStoreKV(t *testing.T) {
 }
 
 func testKVStore(ctx context.Context, t *testing.T, app types.Application, tx []byte, key, value string) {
-	// var (
-	// 	checkTxResp *types.ResponseCheckTx
-	// 	err         error
-	// )
-	// if client, ok := app.(abcicli.Client); ok {
-	// 	checkTxResp, err = client.CheckTxSync(ctx, &types.RequestCheckTx{Tx: tx})
-	// } else {
-	// 	checkTxResp, err = app.CheckTxSyncForApp(ctx, &types.RequestCheckTx{Tx: tx})
-	// }
-	checkTxResp, err := app.CheckTxSyncForApp(ctx, &types.RequestCheckTx{Tx: tx})
+	var (
+		checkTxResp *types.ResponseCheckTx
+		err         error
+	)
+	if client, ok := app.(abcicli.Client); ok {
+		checkTxResp, err = client.CheckTxSync(ctx, &types.RequestCheckTx{Tx: tx})
+	} else {
+		checkTxResp, err = app.CheckTxSyncForApp(ctx, &types.RequestCheckTx{Tx: tx})
+	}
 	require.NoError(t, err)
 	require.Equal(t, uint32(0), checkTxResp.Code)