Add UDFInitializationTests

python/pyspark/sql/tests.py

@@ -469,6 +469,10 @@ def filename(path):
         self.assertTrue(row2[0].find("people.json") != -1)
 
     def test_udf_defers_judf_initalization(self):
+        # This is separate of  UDFInitializationTests
+        # to avoid context initialization
+        # when udf is called
+
         from pyspark.sql.functions import UserDefinedFunction
 
         f = UserDefinedFunction(lambda x: x, StringType())
@@ -1964,6 +1968,29 @@ def test_sparksession_with_stopped_sparkcontext(self):
         df.collect()
 
 
+class UDFInitializationTests(unittest.TestCase):
+    def tearDown(self):
+        if SparkSession._instantiatedSession is not None:
+            SparkSession._instantiatedSession.stop()
+
+        if SparkContext._active_spark_context is not None:
+            SparkContext._active_spark_contex.stop()
+
+    def test_udf_init_shouldnt_initalize_context(self):
+        from pyspark.sql.functions import UserDefinedFunction
+
+        UserDefinedFunction(lambda x: x, StringType())
+
+        self.assertIsNone(
+            SparkContext._active_spark_context,
+            "SparkContext shouldn't be initialized when UserDefinedFunction is created."
+        )
+        self.assertIsNone(
+            SparkSession._instantiatedSession,
+            "SparkSession shouldn't be initialized when UserDefinedFunction is created."
+        )
+
+
 class HiveContextSQLTests(ReusedPySparkTestCase):
 
     @classmethod