diff --git a/spark/dl/src/test/scala/com/intel/analytics/bigdl/serving/InferenceSpec.scala b/spark/dl/src/test/scala/com/intel/analytics/bigdl/serving/InferenceSpec.scala
new file mode 100644
index 00000000000..6d254d55b25
--- /dev/null
+++ b/spark/dl/src/test/scala/com/intel/analytics/bigdl/serving/InferenceSpec.scala
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2018 Analytics Zoo Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.intel.analytics.zoo.serving
+
+import com.intel.analytics.bigdl.tensor.Tensor
+import com.intel.analytics.zoo.serving.utils.{ClusterServingHelper, SerParams}
+import org.scalatest.{FlatSpec, Matchers}
+
+class InferenceSpec extends FlatSpec with Matchers {
+  "TF String input" should "work" in {
+//    val configPath = "/home/litchy/pro/analytics-zoo/config.yaml"
+    val str = "abc|dff|aoa"
+    val eleList = str.split("\\|")
+//    val helper = new ClusterServingHelper(configPath)
+//    helper.initArgs()
+//    val param = new SerParams(helper)
+//    val model = helper.loadInferenceModel()
+//    val res = model.doPredict(t)
+//    res
+  }
+
+}
diff --git a/spark/dl/src/test/scala/com/intel/analytics/bigdl/serving/PreProcessingSpec.scala b/spark/dl/src/test/scala/com/intel/analytics/bigdl/serving/PreProcessingSpec.scala
index c11bcda4b29..956ae21f26a 100644
--- a/spark/dl/src/test/scala/com/intel/analytics/bigdl/serving/PreProcessingSpec.scala
+++ b/spark/dl/src/test/scala/com/intel/analytics/bigdl/serving/PreProcessingSpec.scala
@@ -58,4 +58,12 @@ class PreProcessingSpec extends FlatSpec with Matchers {
     val a = pre.decodeTensor(info)
     a
   }
+  "decode string tensor" should "work" in {
+    val pre = new PreProcessing(null)
+    val str = "abc|dff|aoa"
+    val tensor = pre.decodeString(str)
+    assert(tensor.valueAt(1) == "abc")
+    assert(tensor.valueAt(2) == "dff")
+    assert(tensor.valueAt(3) == "aoa")
+  }
 }