adding shard row id bits test (pingcap#938)

core/src/test/scala/com/pingcap/tispark/datasource/ShardRowIDBitsSuite.scala

@@ -0,0 +1,29 @@
+package com.pingcap.tispark.datasource
+
+import org.apache.spark.sql.Row
+import org.apache.spark.sql.types.{IntegerType, StructField, StructType}
+
+class ShardRowIDBitsSuite extends BaseDataSourceTest("test_shard_row_id_bits") {
+  private val row1 = Row(1)
+  private val row2 = Row(2)
+  private val row3 = Row(3)
+  private val schema = StructType(
+    List(
+      StructField("a", IntegerType)
+    )
+  )
+
+  test("reading and writing a table with shard_row_id_bits") {
+    dropTable()
+    jdbcUpdate(
+      s"CREATE TABLE  $dbtable ( `a` int(11))  SHARD_ROW_ID_BITS = 4"
+    )
+
+    jdbcUpdate(
+      s"insert into $dbtable values(null)"
+    )
+
+    tidbWrite(List(row1, row2, row3), schema)
+    testTiDBSelect(List(Row(null), row1, row2, row3), sortCol = "a")
+  }
+}