add tests and remove pu

Author: adrian-wang

python/pyspark/sql/functions.py

@@ -138,13 +138,6 @@ def _():
     'bitwiseNOT': 'Computes bitwise not.',
 }
 
-_functions_1_5 = {
-    'e': 'Returns the double value that is closer than any other to e, the base of the natural ' +
-         'logarithms.',
-    'pi': 'Returns the double value that is closer than any other to pi, the ratio of the ' +
-          'circumference of a circle to its diameter.'
-}
-
 # math functions that take two arguments as input
 _binary_mathfunctions = {
     'atan2': 'Returns the angle theta from the conversion of rectangular coordinates (x, y) to' +
@@ -195,14 +188,11 @@ def _():
     globals()[_name] = since(1.4)(_create_binary_mathfunction(_name, _doc))
 for _name, _doc in _window_functions.items():
     globals()[_name] = since(1.4)(_create_window_function(_name, _doc))
-for _name, _doc in _functions_1_5.items():
-    globals()[_name] = since(1.5)(_create_function(_name, _doc))
 del _name, _doc
 __all__ += _functions.keys()
 __all__ += _functions_1_4.keys()
 __all__ += _binary_mathfunctions.keys()
 __all__ += _window_functions.keys()
-__all__ += _functions_1_5.keys()
 __all__.sort()
 
 
@@ -358,24 +348,6 @@ def randn(seed=None):
     return Column(jc)
 
 
-@since(1.5)
-def e():
-    """Returns the double value that is closer than any other to e, the base of the natural
-    logarithms.
-    """
-    import math
-    return Column(math.e)
-
-
-@since(1.5)
-def pi():
-    """Returns the double value that is closer than any other to pi, the ratio of the circumference
-    of a circle to its diameter.
-    """
-    import math
-    return Column(math.pi)
-
-
 @since(1.4)
 def sparkPartitionId():
     """A column for partition ID of the Spark task.

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

@@ -106,7 +106,7 @@ object FunctionRegistry {
     expression[Cbrt]("cbrt"),
     expression[Ceil]("ceil"),
     expression[Cos]("cos"),
-    expression[E]("e"),
+    expression[EulerNumber]("e"),
     expression[Exp]("exp"),
     expression[Expm1]("expm1"),
     expression[Floor]("floor"),

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/math.scala

@@ -129,7 +129,7 @@ abstract class BinaryMathExpression(f: (Double, Double) => Double, name: String)
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-case class E() extends LeafMathExpression(math.E, "E")
+case class EulerNumber() extends LeafMathExpression(math.E, "E")
 
 case class Pi() extends LeafMathExpression(math.Pi, "PI")
 

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

@@ -89,7 +89,7 @@ class MathFunctionsSuite extends SparkFunSuite with ExpressionEvalHelper {
   }
 
   test("e") {
-    testLeaf(E, math.E)
+    testLeaf(EulerNumber, math.E)
   }
 
   test("pi") {

sql/core/src/main/scala/org/apache/spark/sql/functions.scala

@@ -951,7 +951,7 @@ object functions {
    * @group math_funcs
    * @since 1.5.0
    */
-  def e(): Column = E()
+  def e(): Column = EulerNumber()
 
   /**
    * Computes the exponential of the given value.

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

@@ -85,6 +85,17 @@ class DataFrameFunctionsSuite extends QueryTest {
     }
   }
 
+  test("constant function") {
+    checkAnswer(
+      testData2.select(e()).limit(1),
+      Row(scala.math.E)
+    )
+    checkAnswer(
+      testData2.select(pi()).limit(1),
+      Row(scala.math.Pi)
+    )
+  }
+
   test("bitwiseNOT") {
     checkAnswer(
       testData2.select(bitwiseNOT($"a")),

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

@@ -145,6 +145,17 @@ class SQLQuerySuite extends QueryTest with BeforeAndAfterAll with SQLTestUtils {
       Seq(Row("1"), Row("2")))
   }
 
+  test("constant functions") {
+    checkAnswer(
+      sql("SELECT E()"),
+      Row(scala.math.E)
+    )
+    checkAnswer(
+      sql("SELECT PI()"),
+      Row(scala.math.Pi)
+    )
+  }
+
   test("SPARK-3176 Added Parser of SQL ABS()") {
     checkAnswer(
       sql("SELECT ABS(-1.3)"),