[SPARK-8810] [SQL] Added several UDF unit tests for Spark SQL

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

@@ -82,6 +82,76 @@ class UDFSuite extends QueryTest {
     assert(ctx.sql("SELECT strLenScala('test', 1)").head().getInt(0) === 5)
   }
 
+  test("UDF in a WHERE") {
+    ctx.udf.register("oneArgFilter", (n: Int) => { n > 80 })
+
+    val df = ctx.sparkContext.parallelize(
+      (1 to 100).map(i => TestData(i, i.toString))).toDF()
+    df.registerTempTable("integerData")
+
+    val result =
+      ctx.sql("SELECT * FROM integerData WHERE oneArgFilter(key)")
+    assert(result.count() === 20)
+  }
+
+  test("UDF in a HAVING") {
+    ctx.udf.register("havingFilter", (n: Long) => { n > 5 })
+
+    val df = Seq(("red", 1), ("red", 2), ("blue", 10),
+      ("green", 100), ("green", 200)).toDF("g", "v")
+    df.registerTempTable("groupData")
+
+    val result =
+      ctx.sql(
+        """
+         | SELECT g, SUM(v) as s
+         | FROM groupData
+         | GROUP BY g
+         | HAVING havingFilter(s)
+        """.stripMargin)
+
+    assert(result.count() === 2)
+  }
+
+  test("UDF in a GROUP BY") {
+    ctx.udf.register("groupFunction", (n: Int) => { n > 10 })
+
+    val df = Seq(("red", 1), ("red", 2), ("blue", 10),
+      ("green", 100), ("green", 200)).toDF("g", "v")
+    df.registerTempTable("groupData")
+
+    val result =
+      ctx.sql(
+        """
+         | SELECT SUM(v)
+         | FROM groupData
+         | GROUP BY groupFunction(v)
+        """.stripMargin)
+    assert(result.count() === 2)
+  }
+
+  test("UDFs everywhere") {
+    ctx.udf.register("groupFunction", (n: Int) => { n > 10 })
+    ctx.udf.register("havingFilter", (n: Long) => { n > 2000 })
+    ctx.udf.register("whereFilter", (n: Int) => { n < 150 })
+    ctx.udf.register("timesHundred", (n: Long) => { n * 100 })
+
+    val df = Seq(("red", 1), ("red", 2), ("blue", 10),
+      ("green", 100), ("green", 200)).toDF("g", "v")
+    df.registerTempTable("groupData")
+
+    val result =
+      ctx.sql(
+        """
+         | SELECT timesHundred(SUM(v)) as v100
+         | FROM groupData
+         | WHERE whereFilter(v)
+         | GROUP BY groupFunction(v)
+         | HAVING havingFilter(v100)
+        """.stripMargin)
+    assert(result.count() === 1)
+  }
+
   test("struct UDF") {
     ctx.udf.register("returnStruct", (f1: String, f2: String) => FunctionResult(f1, f2))