nit

Author: xuanyuanking

sql/core/src/test/scala/org/apache/spark/sql/execution/streaming/state/StreamingAggregationStateManagerSuite.scala

@@ -20,7 +20,7 @@ package org.apache.spark.sql.execution.streaming.state
 import org.apache.spark.sql.catalyst.expressions.{Attribute, SpecificInternalRow, UnsafeProjection, UnsafeRow}
 import org.apache.spark.sql.catalyst.expressions.codegen.GenerateUnsafeProjection
 import org.apache.spark.sql.streaming.StreamTest
-import org.apache.spark.sql.types.{IntegerType, StringType, StructField, StructType}
+import org.apache.spark.sql.types.{IntegerType, StructField, StructType}
 
 class StreamingAggregationStateManagerSuite extends StreamTest {
   // ============================ fields and method for test data ============================