[SPARK-8347][SQL] Add unit tests for abs.

Also addressed code review feedback from apache#6754

Author: Reynold Xin <[email protected]>

Closes apache#6803 from rxin/abs and squashes the following commits:

d07beba [Reynold Xin] [SPARK-8347] Add unit tests for abs.

Author: rxin

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/HiveTypeCoercion.scala

@@ -672,13 +672,13 @@ trait HiveTypeCoercion {
         findTightestCommonTypeToString(left.dataType, right.dataType).map { widestType =>
           val newLeft = if (left.dataType == widestType) left else Cast(left, widestType)
           val newRight = if (right.dataType == widestType) right else Cast(right, widestType)
-          i.makeCopy(Array(pred, newLeft, newRight))
+          If(pred, newLeft, newRight)
         }.getOrElse(i)  // If there is no applicable conversion, leave expression unchanged.
 
       // Convert If(null literal, _, _) into boolean type.
       // In the optimizer, we should short-circuit this directly into false value.
-      case i @ If(pred, left, right) if pred.dataType == NullType =>
-        i.makeCopy(Array(Literal.create(null, BooleanType), left, right))
+      case If(pred, left, right) if pred.dataType == NullType =>
+        If(Literal.create(null, BooleanType), left, right)
     }
   }
 

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/ArithmeticExpressionSuite.scala

@@ -21,7 +21,7 @@ import org.scalatest.Matchers._
 
 import org.apache.spark.SparkFunSuite
 import org.apache.spark.sql.catalyst.dsl.expressions._
-import org.apache.spark.sql.types.{DoubleType, IntegerType}
+import org.apache.spark.sql.types.{Decimal, DoubleType, IntegerType}
 
 
 class ArithmeticExpressionSuite extends SparkFunSuite with ExpressionEvalHelper {
@@ -75,6 +75,21 @@ class ArithmeticExpressionSuite extends SparkFunSuite with ExpressionEvalHelper
     checkDoubleEvaluation(c3 % c2, (1.1 +- 0.001), row)
   }
 
+  test("Abs") {
+    def testAbs(convert: (Int) => Any): Unit = {
+      checkEvaluation(Abs(Literal(convert(0))), convert(0))
+      checkEvaluation(Abs(Literal(convert(1))), convert(1))
+      checkEvaluation(Abs(Literal(convert(-1))), convert(1))
+    }
+    testAbs(_.toByte)
+    testAbs(_.toShort)
+    testAbs(identity)
+    testAbs(_.toLong)
+    testAbs(_.toFloat)
+    testAbs(_.toDouble)
+    testAbs(Decimal(_))
+  }
+
   test("Divide") {
     checkEvaluation(Divide(Literal(2), Literal(1)), 2)
     checkEvaluation(Divide(Literal(1.0), Literal(2.0)), 0.5)

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

@@ -369,23 +369,6 @@ class ColumnExpressionSuite extends QueryTest {
     )
   }
 
-  test("abs") {
-    checkAnswer(
-      testData.select(abs('key)).orderBy('key.asc),
-      (1 to 100).map(n => Row(n))
-    )
-
-    checkAnswer(
-      negativeData.select(abs('key)).orderBy('key.desc),
-      (1 to 100).map(n => Row(n))
-    )
-
-    checkAnswer(
-      testData.select(abs(lit(null))),
-      (1 to 100).map(_ => Row(null))
-    )
-  }
-
   test("upper") {
     checkAnswer(
       lowerCaseData.select(upper('l)),

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

@@ -236,6 +236,18 @@ class MathExpressionsSuite extends QueryTest {
     testOneToOneNonNegativeMathFunction(log1p, math.log1p)
   }
 
+  test("abs") {
+    val input =
+      Seq[(java.lang.Double, java.lang.Double)]((null, null), (0.0, 0.0), (1.5, 1.5), (-2.5, 2.5))
+    checkAnswer(
+      input.toDF("key", "value").select(abs($"key").alias("a")).sort("a"),
+      input.map(pair => Row(pair._2)))
+
+    checkAnswer(
+      input.toDF("key", "value").selectExpr("abs(key) a").sort("a"),
+      input.map(pair => Row(pair._2)))
+  }
+
   test("log2") {
     val df = Seq((1, 2)).toDF("a", "b")
     checkAnswer(

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

@@ -178,18 +178,6 @@ class SQLQuerySuite extends QueryTest with BeforeAndAfterAll with SQLTestUtils {
       Seq(Row("1"), Row("2")))
   }
 
-  test("SPARK-3176 Added Parser of SQL ABS()") {
-    checkAnswer(
-      sql("SELECT ABS(-1.3)"),
-      Row(1.3))
-    checkAnswer(
-      sql("SELECT ABS(0.0)"),
-      Row(0.0))
-    checkAnswer(
-      sql("SELECT ABS(2.5)"),
-      Row(2.5))
-  }
-
   test("aggregation with codegen") {
     val originalValue = sqlContext.conf.codegenEnabled
     sqlContext.setConf(SQLConf.CODEGEN_ENABLED, "true")