test for single seed

sql/core/src/test/scala/org/apache/spark/sql/DataFrameStatSuite.scala

@@ -69,23 +69,21 @@ class DataFrameStatSuite extends QueryTest with SharedSQLContext {
     // rows in each partition.
     val data =
       sparkContext.parallelize(1 to n, 2).mapPartitions(scala.util.Random.shuffle(_)).toDF("id")
-    for (seed <- 1 to 5) {
-      val splits = data.randomSplit(Array[Double](1, 2, 3), seed)
-      assert(splits.length == 3, "wrong number of splits")
+    val splits = data.randomSplit(Array[Double](1, 2, 3), seed = 1)
+    assert(splits.length == 3, "wrong number of splits")
 
-      assert(splits.reduce((a, b) => a.unionAll(b)).sort("id").collect().toList ==
-        data.sort($"id").collect().toList, "incomplete or wrong split")
-
-      for (id <- splits.indices) {
-        assert(splits(id).intersect(splits((id + 1) % splits.length)).collect().isEmpty,
-          s"split $id overlaps with split ${(id + 1) % splits.length}")
-      }
+    assert(splits.reduce((a, b) => a.unionAll(b)).sort("id").collect().toList ==
+      data.sort($"id").collect().toList, "incomplete or wrong split")
 
-      val s = splits.map(_.count())
-      assert(math.abs(s(0) - 100) < 50) // std =  9.13
-      assert(math.abs(s(1) - 200) < 50) // std = 11.55
-      assert(math.abs(s(2) - 300) < 50) // std = 12.25
+    for (id <- splits.indices) {
+      assert(splits(id).intersect(splits((id + 1) % splits.length)).collect().isEmpty,
+        s"split $id overlaps with split ${(id + 1) % splits.length}")
     }
+
+    val s = splits.map(_.count())
+    assert(math.abs(s(0) - 100) < 50) // std =  9.13
+    assert(math.abs(s(1) - 200) < 50) // std = 11.55
+    assert(math.abs(s(2) - 300) < 50) // std = 12.25
   }
 
   test("pearson correlation") {